检索结果-南通市图书馆

Robustness and breakup of the spiral wave in a two-dimensional lattice network of neurons

在线全文

学校读者我要写书评

暂无评论

Science china(Physics,Mechanics & Astronomy) 2010年第4期53卷 672-679页

作者： MA Jun 1,2, TANG Jun 2 , ZHANG AiHua 3 & JIA Ya 2 1 Department of Physics, lanzhou university of technology, lanzhou 73.050, china 2 Department of Physics, Central china Normal university, Wuhan 430079, china 3.college of electrical and information engineering, lanzhou university of technology, lanzhou 73.050, china 1. Department of Physics Lanzhou University of Technology Lanzhou 730050 China2. Department of Physics Central China Normal University Wuhan 430079 China3. College of Electrical and Information Engineering Lanzhou University of Technology Lanzhou 730050 China

The robustness and breakup of spiral wave in a two-dimensional lattice networks of neurons are investigated. The effect of small- world type connection is often simplified with local regular connection and the long-range connection with certain probability. The network effect on the development of spiral wave can be better described by local regular connection and changeable long-range connection probability than fixed long-range connection probability because the long-range probability could be changeable in realistic biological system. The effect from the changeable probability for long-range connection is simplified by multiplicative noise. At first, a stable rotating spiral wave is developed by using appropriate initial values, parameters and no-flux boundary conditions, and then the effect of networks is investigated. Extensive numerical studies show that spiral wave keeps its alive and robust when the intensity of multiplicative noise is below a certain threshold, otherwise, the breakup of spiral wave occurs. A statistical factor of synchronization in two-dimensional array is defined to study the phase transition of spiral wave by checking the membrane potentials of all neurons corresponding to the critical parameters(the intensity of noise or forcing current)in the curve for factor of synchronization. The Hindmarsh-Rose model is investigated, the Hodgkin-Huxley neuron model in the presence of the channel noise is also studied to check the model independence of our conclusions. And it is found that breakup of spiral wave is easier to be induced by the multiplicative noise in presence of channel noise.

关键词： spiral wave factor of synchronization breakup multiplicative noise robustness

On adjacent-vertex-distinguishing total coloring of graphs

在线全文

学校读者我要写书评

暂无评论

Science china Mathematics 2005年第3期48卷 289-299页

作者： ZHANG Zhongfu, CHEN Xiang’en, LI Jingwen, YAO Bing, LU Xinzhong & WANG Jianfang college of Mathematics and information Science, Northwest Normal university, lanzhou 730070, china Department of Computer, lanzhou Normal college, lanzhou 730070, china Institute of Applied Mathematics, lanzhou Jiaotong university, lanzhou 730070, china college of information and electrical engineering, lanzhou Jiaotong university, lanzhou 730070, china Institute of Applied Mathematics, Chinese Academy of Sciences, Beijing 100080, china 1. college of Mathematics and information Science Northwest Normal University 730070 Lanzhou China 2. Department of Computer Lanzhou Normal College 730070 Lanzhou China 3. Institute of Applied Mathematics Lanzhou Jiaotong University 730070 Lanzhou China 4. college of information and electrical engineering Lanzhou Jiaotong University 730070 Lanzhou China 5. Institute of Applied Mathematics Chinese Academy of Sciences 100080 Beijing China

In this paper, we present a new concept of the adjacent-vertex-distinguishing total coloring of graphs (briefly, AVDTC of graphs) and, meanwhile, have obtained the adjacent-vertex-distinguishing total chromatic number... 详细信息

关键词： graph, proper total coloring, adjacent-vertex-distinguishing total coloring, adjacent-vertex-distinguishing total chromatic number.

Optimal design study of high order FIR digital filters based on neural network algorithm

在线全文

学校读者我要写书评

暂无评论

Journal of Systems engineering and Electronics 2004年第2期15卷 115-119,130页

作者： Wang Xiaohua & He Yigangcollege of electrical and information engineering, Hunan university, Changsha 410082, P. R. china college of electrical and information engineering, Changsha university of Science and technology,Changsha 410077, P. R. china college of electrical and information engineering Hunan University Changsha 410082 P. R. China college of electrical and information engineering Changsha University of Science and Technology Changsha 410077 P. R. China

An optimal design approach of high order FIR digital filter is developed based on the algorithm of neural networks with cosine basis function . The main idea is to minimize the sum of the square errors between the amplitude response of the desired FIR filter and that of the designed by training the weights of neural networks, then obtains the impulse response of FIR digital filter . The convergence theorem of the neural networks algorithm is presented and proved, and the optimal design method is introduced by designing four kinds of FIR digital filters , i.e., low-pass, high-pass, bandpass , and band-stop FIR digital filter. The results of the amplitude responses show that attenuation in stop-bands is more than 60 dB with no ripple and pulse existing in pass-bands, and cutoff frequency of passband and stop-band is easily controlled precisely .The presented optimal design approach of high order FIR digital filter is significantly effective.

关键词： high order FIR digital filters amplitude-frequency response neural network convergence theorem optimal design.

Approximately optimal tracking control for discrete time-delay systems with disturbances

在线全文

学校读者我要写书评

暂无评论

Progress in Natural Science:Materials International 2008年第2期18卷 225-231页

作者： Gongyou Tang a,,Huiying Sun b,Haiping Pang c a college of information Science and engineering,Ocean university of china,Qingdao 266100,china b college of information and electrical engineering,Shandong university of Science and technology,Qingdao 266510,china c college of Automation and Electronic engineering,Qingdao university of Science and technology,Qingdao 266042,china college of information Science and engineering Ocean University of China Qingdao 266100 China college of information and electrical engineering Shandong University of Science and Technology Qingdao 266510 China college of Automation and Electronic engineering Qingdao University of Science and Technology Qingdao 266042 China

Optimal tracking control (OTC) for discrete time-delay systems affected by persistent disturbances with quadratic performance index is considered. By introducing a sensitivity parameter,the original OTC problem is transformed into a series of two-point boundary value (TPBV) problems without time-advance or time-delay terms. The obtained OTC law consists of analytic feedforward and feedback terms and a compensation term which is the sum of an infinite series of adjoint vectors. The analytic feedforward and feedback terms can be found by solving a Riccati matrix equation and two Stein matrix equations. The compensation term can be obtained by using an iteration formula of the adjoint vectors. Observers are constructed to make the approximate OTC law physically realizable. A simulation example shows that the approximate approach is effective in tracking the reference input and robust with respect to exogenous persistent disturbances.

关键词： Discrete systems Time-delay systems Disturbances Optimal control Tracking control

Characteristics and origins of primary fluids and noble gases in mantle-derived minerals from the Yishu area,Shandong Province,china

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Science china Earth Sciences 2006年第1期49卷 77-87页

作者： MA Jinlong1,2, TAO Mingxin2,3 & YE Xianren2 1. Resources and Environmental School, lanzhou university, lanzhou 730000, china 2. Key Laboratory of Gas Geochemistry, Institute of Geology and Geophysics, Chinese Academy of Sciences, lanzhou 730000, china 3. college of Resources Science & technology, Beijing Normal university, Beijing 100875, china 1. Resources and Environmental School Lanzhou University Lanzhou 730000 China 2. Key Laboratory of Gas Geochemistry Institute of Geology and Geophysics Chinese Academy of Sciences Lanzhou 730000 China 3. college of Resources Science & technology Beijing Normal University Beijing 100875 China

Fluids and noble gases of mantle-derived materials are important tracers forthe mantle information. Compositions of primary fluids and noble gases in mantle-derived mineralsfrom the Yishu area, Shandong Province, china, were tested by the methods of heat-bursting andheat-melting respectively. The fluids are mainly composed of CO_2, CO and H_2, which account forabout 90% of the total, and are similar to the mantle-derived rocks from other areas of easternchina; ratios of ~3He/~4He in almost all samples range from 0.82 Ra to 2.74 Ra, whereas^(40)Ar/^(36)Ar from 299.5 to 758.8. Both ranges are much lower than those of the typical oceanmantle-derived samples (such as MORB) and primarily reflect the influences of the atmosphericcomponents and the radiogenic isotopes. Ratios of C/~3He range from 27.6 x 10~9 to 1050 x 10~9,N_2/Ar from 927 to 56612, and N_2/~3He from 2.5 x 10~9 to 27 x 10~9, similar to those in westernUnited States and New Zealand which belong to the tectonic plate collision regions. The ratios fallin the intersect of mantle-crust-atmosphere in the comprehensive tracer-charts, reflecting theinfluences of the atmosphere and the crusts with organic components. Our results suggest that thecomposition of the primary fluids and the isotopic ratios of the noble gases may either reflect theevolution process of mantle-derived rocks connected with the rise and eruption of magma, or theinfluence of the ancient subduction-plate on the continental mantle of this region.

关键词： noble gases, primary fluids, mantle-derived minerals, Yishu area.

Short cycle structures for graphs on surfaces and an open problem of Mohar and Thomassen

在线全文

学校读者我要写书评

暂无评论

Science china Mathematics 2006年第2期49卷 212-224页

作者： REN Han & DENG Mo Department of Mathematics, East china Normal university, Shanghai 200062, china college of Mathematics & information Science, Northwest Normal university, lanzhou 730070, china 1. Department of Mathematics East China Normal University Shanghai 200062 China 2. college of Mathematics & information Science Northwest Normal University Lanzhou 730070 China

In this paper we investigate cycle base structures of a (weighted) graph and show that much information of short cycles is contained in an MCB (i.e., minimum cycle base). After setting up a Hall type theorem for base-transformation, we give a sufficient and necessary condition for a cycle base to be an MCB. Furthermore, we show that the structure of MCB in a (weighted)graph is unique. The property is also true for those having a longest length (although much work has been down in evaluating MCB, little is known for those having a longest length). We use those methods to find out some unknown properties for short cycles sharing particular properties in (unweighted) graphs. As applications, we determine the structures of short cycles in an embedded graph and show that there exist polynomially bounded algorithms in finding a shortest contractible cycle and a shortest two-sided cycle provided such cycles exist. Those answer an open problem of B. Mohar and C. Thomassen.

关键词： cycle base facial cycle graph embedding.

Series-based approximate approach of optimal tracking control for nonlinear systems with time-delay

在线全文

学校读者我要写书评

暂无评论

Progress in Natural Science:Materials International 2008年第12期18卷 1571-1576页

作者： Gongyou Tang~a Mingqu Fan~(a,b) a college of information Science and engineering,Ocean university of china,Qingdao 266100,china b college of information and engineering,Shandong university of Science and technology,Jinan 250031,china [a]college of information Science and engineering Ocean University of China Qingdao 266100 China [b]college of information and engineering Shandong University of Science and Technology Jinan 250031 China

The optimal output tracking control (OTC) problem for nonlinear systems with time-delay is *** a series-based approx- imate approach,the original OTC problem is transformed into iteration solving linear two-point boundary value problems without time- *** OTC law obtained consists of analytical linear feedback and feedforward terms and a nonlinear compensation term with an infinite series of the adjoint *** truncating a finite sum of the adjoint vector series,an approximate optimal tracking control law is obtained.A reduced-order reference input observer is constructed to make the feedforward term physically *** exam- ples are used to test the validity of the series-based approximate approach.

关键词： Nonlinear systems Time-delay Tracking control Optimal control Observer

RBF neural network and active circles based algorithm for contours extraction

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Progress in Natural Science:Materials International 2007年第6期17卷 681-686页

作者： Zhou Zhiheng, Zeng Delu and Xie Shengli(college of Electronic & information engineering, South china university of technology, Guangzhou 510640, china) college of Electronic and information engineering South China University of Technology Guangzhou 510640 China

For the contours extraction from the images, active contour model and self-organizing map based approach are popular nowadays. But they are still confronted with the problems that the optimization of energy function will trap in local minimums and the contour evolutions greatly depend on the initial contour selection. Addressing to these problems, a contours extraction algorithm based on RBF neural network is proposed here. A series of circles with adaptive radius and center is firstly used to search image feature points that are scattered enough. After the feature points are clustered, a group of radial basis functions are constructed. Using the pixels’ intensities and gradients as the input vector, the final object contour can be obtained by the predicting ability of the neural network. The RBF neural network based algorithm is tested on three kinds of images, such as changing topology, complicated background, and blurring or noisy boundary. Simulation results show that the proposed algorithm performs contours extraction greatly.

关键词： contours extraction RBF neural network dynamic clustering.

Vector bundle constraint for particle swarm optimization and its application to active contour modeling

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Progress in Natural Science:Materials International 2007年第10期17卷 1220-1225页

作者： Zeng Delu, Zhou Zhiheng and Xie Shengli(college of Electronic and information engineering, South china university of technology, Guangzhou 510641, china) college of Electronic and information engineering South China University of Technology Guangzhou 510641 China

Active contour modeling (ACM) has been shown to be a powerful method in object boundary extraction. In this paper, a new ACM based on vector bundle constraint for particle swarm optimization (VBCPSO-ACM) is proposed. Different from the traditional particle swarm optimization (PSO), in the process of velocity update, a vector bundle is predefined for each particle and velocity update of the particle is restricted to its bundle. Applying this idea to ACM, control points on the contour are treated as particles in PSO and the evolution of the contour is driven by the particles. Meanwhile, global searching is shifted to local searching in ACM by decreasing the number of neighbors and inertia. In addition, the addition and deletion of particles on the active contour make this new model possible for representing the real boundaries more precisely. The proposed VBCPSO-ACM can avoid self-intersection during contour evolving and also extract inhomogeneous boundaries. The simulation results proved its great performance in performing contour extraction.

关键词： boundary extraction active contour modeling particle swarm optimization velocity update vector bundle.