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Progress in Natural Science:Materials International 2007年第3期17卷 340-345页

作者： xiE Xuemei (School of Electronic Engineering, xidian University, xi’an 710071, China) School of Electronic Engineering Xidian University Xi'an 710071 China

In this paper, a method is proposed to construct recombination nonuniform cosine-modulated filter banks (CMFBs) with a perfect-reconstruction property and with arbitrary filter lengths. In this filter bank (FB) structure, certain channels of an original M-channel uniform FB are merged by a set of transmultiplexers (TMUXs), yielding nonuniform outputs, and the length restrictions on the original CMFB and the recombination TMUXs are avoided, allowing them to have arbitrary filter lengths. By imposing certain improved matching conditions on the prototype filters, nonuniform FBs with arbitrary filter lengths and with good properties can be obtained. As a result, the flexibility of selecting modulation types and filter lengths is greatly increased in the design of recombination nonuniform CMFBs. Another benefit due to the flexibility is that the system delay can be reduced.

关键词： recombination nonunlform cosine-modulated filter bank transmultiplexer perfect-reconstruction arbitrary-length.

FUZZY OPTIMIZATION MODEL OF MAINTENANCE DESIGN FOR PRODUCT LEVEL REUSE

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Chinese Journal of Mechanical Engineering 2004年第2期17卷 197-199页

作者： Feng Zhen Xu Guohua School of ElectromechanicalEngineering,xidian University,xi’an 710071, China School of Electro-mechanical Engineering Xidian University Xi'an 710071

Most used products must be maintained before they are reused. The modelingmethod for maintenance design of product level reuse based on quality function deployment ispresented. A fuzzy linear optimization model is developed under financial uncertainty. Objective ofthe model is to maximize improvement rate of customer satisfaction level. Maintenance cost constrainis fuzzy. The algorithm for solution to the model is given. Its optimized results not only giveattention to satisfaction degree of cost constraint, but also maximize objective value. Anillustrative example involved water bump reuse is studied and the results show that the proposedmodel can effectively help maintenance planner determine the better design scheme.

关键词： Product level reuse Maintenance design Quality function deployment Fuzzylinear programming

维普期刊数据库

A novel evolutionary algorithm for global numerical optimization with continuous variables

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Progress in Natural Science:Materials International 2008年第3期18卷 345-351页

作者： Wenhong Zhaoa,b, Wei Wang a, Yuping Wang a, a School of Computer Science and Technology, xidian University, xi’an 710071, China b Faculty of Science, xidian University, xi’an 710071, China School of Computer Science and Technology Xidian University Xi’an 710071 China Faculty of Science Xidian University Xi’an 710071 China

Evolutionary algorithms (EAs) are a class of general optimization algorithms which are applicable to functions that are multimodal, non-differentiable, or even discontinuous. In this paper, a novel evolutionary algorithm is proposed to solve global numerical optimiza- tion with continuous variables. In order to make the algorithm more robust, the initial population is generated by combining determinate factors with random ones, and a decent scale function is designed to tailor the crossover operator so that it can not only find the decent direction quickly but also keep scanning evenly in the whole feasible space. In addition, to improve the performance of the algorithm, a mutation operator which increases the convergence-rate and ensures the convergence of the proposed algorithm is designed. Then, the global convergence of the presented algorithm is proved in detail. Finally, the presented algorithm is executed to solve 24 benchmark problems, and the results show that the convergence-rate of the proposed algorithm is much faster than that of the compared algorithms.

关键词： Evolutionary algorithm Decent scale function Global numerical optimization Global convergence

Small-amplitude solitons in nonlinear-saturation glass fibers

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Chinese Journal of Lasers 1995年第1期B4卷 37-46页

作者： YU Zhongyuan CHEN Lujun (Department of Physics,xidian University,xi an 710071,China) xidian Univ Xi'an China

Ｓｍａｌｌ－ａｍｐｌｉｔｕｄｅｓｏｌｉｔｏｎｓｉｎｎｏｎｌｉｎｅａｒ－ｓａｔｕｒａｔｉｏｎｇｌａｓｓｆｉｂｅｒｓＳｍａｌｌ－ａｍｐｌｉｔｕｄｅｓｏｌｉｔｏｎｓｉｎｎｏｎｌｉｎｅａｒ－ｓａｔｕｒａｔｉｏｎｇｌａｓｓｆｉ... 详细信息

Ｓｍａｌｌ－ａｍｐｌｉｔｕｄｅｓｏｌｉｔｏｎｓｉｎｎｏｎｌｉｎｅａｒ－ｓａｔｕｒａｔｉｏｎｇｌａｓｓｆｉｂｅｒｓＳｍａｌｌ－ａｍｐｌｉｔｕｄｅｓｏｌｉｔｏｎｓｉｎｎｏｎｌｉｎｅａｒ－ｓａｔｕｒａｔｉｏｎｇｌａｓｓｆｉｂｅｒｓ￥ＹＵＺｈｏｎｇｙｕａｎ；...

关键词： optical soliton nonlinear-saturation medium semiconductor-doped fiber

Construction of almost optimal resilient Boolean functions via concatenating Maiorana-McFarland functions

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Science China(Information Sciences) 2011年第4期54卷 909-912页

作者： ZHANG WeiGuo & xiAO GuoZhen ISN Laboratory,xidian University,xi’an 710071,China ISN Laboratory Xidian University Xi’an China

We describe a method to construct an n-variable (n even) almost optimal resilient Boolean function via concatenating 2 d properly chosen (n-d)-variable Maiorana-McFarland *** an example,a 5-resilient 42-variable Boole... 详细信息

关键词： Boolean functions nonlinearity resiliency stream ciphers

Adaptive Iterative Learning Control for Nonlinearly Parameterized Systems with Unknown Time-varying Delay and Unknown Control Direction

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International Journal of Automation and computing 2012年第6期9卷 578-586页

作者： Dan Li Jun-Min Li Department of Mathematics,xidian University,xi an 710071,China Department of Mathematics Xidian University Xi’an China

This paper proposes a new adaptive iterative learning control approach for a class of nonlinearly parameterized systems with unknown time-varying delay and unknown control *** employing the parameter separation technique and signal replacement mechanism,the approach can overcome unknown time-varying parameters and unknown time-varying delay of the nonlinear *** incorporating a Nussbaum-type function,the proposed approach can deal with the unknown control direction of the nonlinear *** on a Lyapunov-Krasovskii-like composite energy function,the convergence of tracking error sequence is achieved in the iteration ***,two simulation examples are provided to illustrate the feasibility of the proposed control method.

关键词： Nonlinearly time-varying parameterized systems unknown time-varying delay unknown control direction composite energy function adaptive iterative learning control.

维普期刊数据库

SYNTHESIS AND ANALYSIS OF A FEEDBACK CONTROL SYSTEM

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Systems Science and Mathematical Sciences 1993年第4期6卷 312-319页

作者： ZHOU Rongxing xi’an Electronic Polytechnic Univcrsity, xi’an 710071, China 西安电子科技大学陕西西安

In this paper, supposing that the received signals at the input are of the formv（t）=s1[t, x1（t）]s2[t, x2（t）]+n（t） where si are FM signals （i=1, 2）, a novel cross-coupledphase-locked loop （CCPLL（M）） and its mathematical model are obtained. The globalqualitativestructural analysis of the mathematical model of the first-order loop, the acqui-sition region and synchronization region of the first-order loop, and the synchronizationregion of the second-order loop are obtained.

关键词： Feedback control mathematical model toral equations qualitative analysis CCPLL

维普期刊数据库

Artificial immune kernel clustering network for unsupervised image segmentation

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Progress in Natural Science:Materials International 2008年第4期18卷 455-461页

作者： Wenlong Huang , Licheng Jiao Institute of Intelligent Information Processing, xidian University, xi’an 710071, China Institute of Intelligent Information Processing Xidian University Xi’an 710071 China

An immune kernel clustering network (IKCN) is proposed based on the combination of the artificial immune network and the sup- port vector domain description (SVDD) for the unsupervised image segmentation. In the network, a new antibody neighborhood and an adaptive learning coeffcient, which is inspired by the long-term memory in cerebral cortices are presented. Starting from IKCN algo- rithm, we divide the image feature sets into subsets by the antibodies, and then map each subset into a high dimensional feature space by a mercer kernel, where each antibody neighborhood is represented as a support vector hypersphere. The clustering results of the local support vector hyperspheres are combined to yield a global clustering solution by the minimal spanning tree (MST), where a predfined number of clustering is not needed. We compare the proposed methods with two common clustering algorithms for the artificial synthetic data set and several image data sets, including the synthetic texture images and the SAR images, and encouraging experimental results are obtained.

关键词： Artificial immune network Kernel mapping Nonsubsampled contourlet transform Unsupervised image segmentation

Doubly selective channel estimation for subband OFDMA using basis expansion models

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Science China(Information Sciences) 2011年第10期54卷 2113-2123页

作者： CHEN DongHua & QIU HongBing School of Telecommunications Engineering,xidian University,xi’an 710071,China School of Telecommunications Engineering Xidian University Xi’an China

This letter considers the channel estimation for subband orthogonal frequency division multiple access (OFDMA) operating over highly time-frequency selective (i.e.,doubly selective) *** on general basis expansion model,two expectation maximization-type channel estimation methods are proposed for subband OFDMA in order to overcome channel time-frequency *** proposed method is compared with conventional approach and is shown to be superior to the conventional one.

关键词： orthogonal frequency division multiple access channel estimation basis expansion model expectation maximization algorithm time-frequency selectivity

Analysis of PR and near-PR cosine-modulated filter banks with odd and even numbers of channels

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Progress in Natural Science:Materials International 2006年第11期16卷 1198-1204页

作者： xiE Xuemei**, ZHONG Wei and SHI Guangming(School of Electronic Engineering, xidian University, xi’an 710071, China) School of Electronic Engineering Xidian University Xi'an 710071 China

It is well known that M-channel filter banks, satisfying either the perfect-reconstruction (PR) or near-PR property, can be obtained by cosine modulation of a linear-phase prototype filter. In this work, we investigated the effects of choosing odd or even number of channels on the performance of both PR and near-PR cosine-modulated filter banks (CMFBs). Given the same m, a performance degradation happens in the PR case with odd numbered M. Contrarily, the choice of even or odd M has little effects on the whole system quality for near-PR one. In addition, we made some comparisons between the constrained optimization and the Parks-McClellan algorithm with cosine roll-off characteristic in designing near-PR CMFBs. Detailed analyses and numerical comparisons show that the PR and near-PR systems have their individual characteristics in terms of M and m selection. Studies here can provide useful and practical guidelines for choosing right filter systems.

关键词： cosine modulated filter banks perfect reconstruction (PR) the Parks-McClellan algorithm.