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COMPLEXITY ANALYSIS OF NETWORK-BASED DYNAMICAL SYSTEMS

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Journal of Systems science & Complexity 2011年第3期24卷 413-432页

作者： Guofeng ZHANG Long WANG Tongwen CHEN School of Electronic engineering University of Electronic Science and Technology of China Chengdu 610054 China. Intelligent Control Laboratory Center for Systems and Control College of Engineering Peking University Beijing 100871 China department of electrical and computer engineering University of Alberta Edmonton Alberta T6G 2V4 Canada

This paper investigates the nonlinear dynamics of network-based dynamical systems where network communication channels of finite data rates are inserted into the closed loops of the control systems. The authors analyze the bifurcation and chaotic behavior of the non-smooth dynamical systems. The authors first prove that for almost all system parameters there are no periodic orbits. This result distinguishes this type of non-smooth dynamical systems from many others exhibiting border-collision bifurcations. Next, the authors show analytically that the chaotic sets are separated from the region containing the line segment of all fixed points with a finite distance. Finally, the authors employ a simple model to highlight that both the number of clients sharing a common network channel and fluctuations in the available network bandwidth have significant influence on the performance of such dynamical systems.

关键词： Bifurcation feedback network-based dynamical system non-convexity periodicity.

Image stylization with enhanced structure on GPU

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science china(Information sciences) 2012年第5期55卷 1093-1105页

作者： LI Ping 1,SUN HanQiu 1,SHENG Bin 1,2 & SHEN JianBing 3 1 department of computer science and engineering,The Chinese university of Hong Kong,Hong Kong,china 2 department of computer science and engineering,Shanghai Jiao Tong university,Shanghai 200240,china 3 School of computer science and Technology,beijing Institute of Technology,beijing 100081,china department of computer science and engineering The Chinese University of Hong Kong Hong Kong China department of computer science and engineering Shanghai Jiao Tong University Shanghai China School of computer science and Technology Beijing Institute of Technology Beijing China

This paper presents a graphics processing unit (GPU) based stylization approach that preserves the fine structure between the original and the stylized images using gradient *** abstraction and painterly stylization methods focused on contrast manipulation only,and thus the detailed salient structures of the input images are always destroyed when performing the current stylization techniques because of limitations like unavoidable salience information loss caused by contrast *** propose an image structure map to naturally model the fine structure existing in the original ***-based structure tangent generation and tangent-guided image morphology are used to construct the structure *** image structure map,unlike an edge map,not only systematically models the boundary information within the imagery but also accentuates the underlying inner structure detail for further *** facilitate the final stylization via parallel bilateral grid and structure-aware stylizing optimization on a GPU-CUDA platform in real *** multiple experiments,the proposed method consistently demonstrates efficient and high quality image stylization performance.

关键词： image stylization non-photorealistic rendering real-time processing GPU image abstraction

Spatial continuity incorporated multi-attribute fuzzy clustering algorithm for blood vessels segmentation

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science china(Information sciences) 2010年第4期53卷 752-759页

作者： HAO JuTao1*, ZHAO JingJing2 & LI MingLu3 1School of Optical-electrical and computer engineering, university of Shanghai for science and Technology, Shanghai 200093, china 2department of electrical engineering, Shanghai university of Electric Power, Shanghai 200090, china 3department of computer science and engineering, Shanghai Jiaotong university, Shanghai 200240, china School of Optical-electrical and computer engineering University of Shanghai for Science and Technology Shanghai China department of electrical engineering Shanghai University of Electric Power Shanghai China department of computer science and engineering Shanghai Jiaotong University Shanghai China

A three-dimensional representation of vasculature can be extremely important in image-guided neurosurgery, pre-surgical planning. In this paper, a spatial continuity incorporated multi-attribute fuzzy clustering algorithm (MAFCM S) is proposed to segment entire blood vessels from TOF MRA images. This clustering method takes both the intensity information and the geometrical information into account, while most of the cur- rent clustering methods only deal with the former. In this method, a new dissimilarity measure, which integrates the intensity and the geometry shape dissimilarity, is introduced. Because of the presence of the geometrical information, the new measure is able to differentiate the pixels with similar intensity values within different geometrical shape structures. Experimental results show that the new algorithm can get better segmentation.

关键词： fuzzy c-means clustering scale space analysis spatial continuity blood vessel segmentation multi-attribute fuzzy clustering

Fractal structure reconstruction for alumina-silicate refractory fiber and simulation of the thermal conductivity

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Journal of Thermal science 2010年第1期19卷 80-86页

作者： XIA Dehong,GUO Shanshan,and Ren Ling department of Thermal engineering,university of science and Technology beijing,beijing 100083,china department of Thermal engineering University of Science and Technology Beijing Beijing China

In this paper, it is proved that the intemal porous structure of alumina-silicate refractory fiber has fractal characteristics, which is reconstructed by the computer and the reconstructed structure further proved to have fractal characteristics. Based on the reconstructed structure, the network-thermal-resistance model is established to calculate the thermal conductivity of the fiber. It is shown that the calculated results agree well with the previous experimental ones, proving the correctness of the method.

关键词： fractal refractory fiber thermal conductivity

A Routing Algorithm for Distributed Optimal Double Loop computer Networks

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Journal of Systems engineering and Electronics 1994年第1期5卷 37-43页

作者： Li Layuan(department of electrical engineering and computer science.Wuhan university of Water Transportation, Wuhan 430063, P. R. china) department of electrical engineering and computer science Wuhan University of Water Transportation Wuhan 430063 P.R. China

A routing algorithm for distributed optimal double loop computer networks is proposed and analyzed. In this paper, the routing algorithm rule is described, and the procedures realizing the algorithm are given. The proposed algorithm is shown to be optimal and robust for optimal double loop. In the absence of failures,the algorithm can send a packet along the shortest path to destination; when there are failures,the packet can bypasss failed nodes and links.

关键词： computer networks Double loop Routing algorithm

A low power and small area all digital delay-locked loop based on ring oscillator architecture

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science china(Information sciences) 2012年第2期55卷 453-460页

作者： ZHENG JiaPeng1,LI Wei2,LU XueQing2,CHENG YuHua1 & WANG YangYuan1 1department of Microelectronics,School of Electronics engineering and computer science,peking university,beijing 100871,china 2Semiconductor Manufacturing International Corp,Shanghai 201203,china department of Microelectronics School of Electronics Engineering and Computer Science Peking University Beijing China Semiconductor Manufacturing International Corp Shanghai China

A 133-500 MHz,5.2 mW @500 MHz,0.021 mm2 all digital delay-locked loop(ADDLL)is *** power and area reduction of the proposed ADDLL are achieved by implementing a high frequency ring oscillator(ROSC)to count the reference clocks such that the one-clock cycle delay chain and the phase detector in a conventional Master block are no longer *** proposed ADDLL has better immunity to PVT(process,voltage,and temperature)than most conventional DLLs,which do not update the control word signals after the locking process,since the control signals for slave delay line are updated in every 256 reference *** in 0.13 um CMOS process,the measured RMS jitter is 10.83 ps at 500 MHz while the RMS jitter of the input signal is 9.97 ps.

关键词： all digital delay locked loop(DLL) phase locked loop(PLL) ring oscillator

Fast parallel algorithms for discrete Gabor expansion and transform based on multirate filtering

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science china(Information sciences) 2012年第2期55卷 293-300页

作者： TAO Liang1 & GU JuanJuan2 1School of computer science and Technology,Anhui university,Hefei 230039,china 2department of Electronic Information and electrical engineering,Hefei university,Hefei 230022,china School of computer science and Technology Anhui University Hefei China department of Electronic Information and electrical engineering Hefei University Hefei China

The Gabor transform has long been recognized as a very useful tool for the joint time and frequency analysis in signal *** real time applications,however,were limited due to the high computational complexity of the Gabor transform *** this paper,some novel and fast parallel algorithms for the finite discrete Gabor expansion and transform are presented based on multirate *** analysis filter bank is designed for the finite discrete Gabor transform(DGT)and a synthesis filter bank is designed for the finite discrete Gabor expansion(DGE).Each of the parallel channels in the two filter banks has a unified structure and can apply the FFT and the IFFT to reduce its computational *** computational complexity of each parallel channel does not change as the oversampling rate *** fact,it is very low and depends only on the length of the input discrete signal and the number of the Gabor frequency sampling *** computational complexity of the proposed parallel algorithms is analyzed and compared with that of the major existing parallel algorithms for the finite DGT and *** results indicate that the proposed parallel algorithms for the finite DGT and DGE based on multirate filtering are very attractive for real time signal processing.

关键词： discrete Gabor expansion discrete Gabor transform critical sampling and oversampling multirate filtering analysis and synthesis filter banks

Parameter identification theory of a complex model based on global optimization method

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science china(Physics,Mechanics & Astronomy) 2008年第11期51卷 1722-1732页

作者： QU Jie1, JIN QuanLin2 & XU BingYe3 1 College of Automotive engineering, South china university of Technology, Guangzhou 510640, china 2 beijing Research Institute of Mechanical and electrical Technology, beijing 100083, china 3 department of engineering Mechanics, Tsinghua university, beijing 100084, china College of Automotive engineering South China University of Technology Guangzhou China beijing Research Institute of Mechanical and electrical Technology Beijing China department of engineering Mechanics Tsinghua University Beijing China

With the development of computer technology and numerical simulation technology, computer aided engineering (CAE) technology has been widely applied to many fields. One of the main obstacles, which hinder the further application of CAE technology, is how to successfully identify the parameters of the selected model. An elementary framework for parameter identification of a complex model is provided in this paper. The framework includes the construction of objective function, the design of the optimization method and the evaluation of the identified results, etc. The parameter identification process is described in this framework, taking the parameter identification of the superplastic constitutive model considering grain growth for Ti-6Al-4V at 927°C as an example. The objective function is the weighted quadratic sums of the difference between the experimental and computational data for the stress-strain relationship and the grain growth relationship; the designed optimization method is a hybrid global optimization method, which is based on the feature of the objective function and incorporates the strengths of genetic algorithm (GA), the Levenberg-Marquardt algorithm and the augmented Gauss-Newton algorithm. The reliability evaluation of parameter identification result is made through the comparison between the calculated and experimental results and between the theoretical values of the parameters and the identified ones.

关键词： constitutive model parameter identification theory inverse analysis global optimization

Building a next generation Internet with source address validation architecture

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science in china(Series F) 2008年第11期51卷 1681-1691页

作者： WU JianPing1,3,REN Gang1,3 & LI Xing2,3 1 department of computer science,Tsinghua university,beijing 100084,china 2 department of Electronic engineering,Tsinghua university,beijing 100084,china 3 Tsinghua National Laboratory for Information science and Technology(TNList) ,beijing 100084,china department of computer science Tsinghua University Beijing China Tsinghua National Laboratory for Information science and Technology (TNList) Beijing China department of Electronic engineering Tsinghua University Beijing China

The IP packet forwarding of current Internet is mainly destination based. In the forwarding process, the source IP address is not checked in most *** causes serious security, management and accounting problems. Based on the drastically increased IPv6 address space, a ＂source address validation architecture＂（SAVA） is proposed in this paper, which can guarantee that every packet received and forwarded holds an authenticated source IP address. The design goals of the architecture are lightweight, loose coupling, ＂multi-fence support＂ and incremental deployment. This paper discusses the design and implementation for the architecture, including inter-AS, intra-AS and local subnet. The performance and scalability of SAVA are described. This architecture is deployed into the CNGI-CERNET2 infrastructure a large-scale native IPv6 backbone network of the china Next Generation Internet project. We believe that the SAVA will help the transition to a new, more secure and dependable Internet.

关键词： IP source address validation network architecture network security