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Algorithm of simulation time synchronization over large-scale nodes

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Science in China(Series F) 2008年第9期51卷 1239-1255页

作者： ZHAO QinPing1,2.ZHOU Zhong1,2.& Lü Fang1,2.1 State Key Laboratory of Virtual Reality Technology and Systems,Beihang university,Beijing 100083,China 2.school of {2. Science and engineering,Beihang university,Beijing 100083,China State Key Laboratory of Virtual Reality Technology and Systems Beihang University Beijing 100083 China school of computer Science and {2. Beihang University Beijing 100083 China

In distributed simulation, there is no uniform physical clock. And delay cannot be estimated because of jitter. So simulation time synchronization is essential for the event consistency among nodes. This paper investigates time synchronization algorithms over large-scale distributed nodes, analyzes LBTS （lower bound time stamp） computation model described in IEEE HLA standard, and then presents a grouped LBTS model. In fact, there is a default premise for existing algorithms that controi packets must be delivered via reliable transportation. Although, a theorem of time synchronization message＇s reliability is proposed, which proves that only those control messages that constrain time advance need reliability. It breaks out the default premise for reliability. Then multicast is introduced into the transmis- sion of control messages, and algorithm MCTS （multi-node coordination time synchronization） is proposed based on multicast. MCTS not only promotes the time advance efficiency, but also reduces the occupied network bandwidth. Experiment results demonstrate that the algorithm is better than others in both time advance speed and occupied network bandwidth. Its time advance speed is about 50 times per second when there are 1000 nodes, approximately equal to that of similar systems when there are 100 nodes.

关键词： distributed simulation time synchronization multi-node coordination LBTS multicast

Normal scalar curvature and a pinching theorem in S^m×R and H^m×R

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Science China mathematics 2011年第9期54卷 1977-1984页

作者： CHEN Qun 1,2.& CUI Qing 3,1,1 school of mathematics and Statistics,Wuhan {2.,Wuhan 430079,China 2.International Center for Theoretical Physics,Trieste 34100,Italy 3 school of mathematics,Southwest Jiaotong {2.,chengdu 610031,China school of mathematics and Statistics Wuhan University Wuhan China International Center for Theoretical Physics Trieste Italy school of mathematics Southwest Jiaotong University Chengdu China

We obtain an inequality in Sm×R and Hm×R which is similar to DDVV *** an application,we show that a minimal submanifold in H m×R with nonnegative scalar curvature must be a surface of the type γ×R,where γ is a g... 详细信息

关键词： product spaces DDVV conjecture pinching theorem

Optical multipath self-interference cancellation for a wideband in-band full-duplex system using a silicon photonic modulator chip

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Chinese Optics Letters 2024年第7期22卷 126-131页

作者： Xiao Yu Jia Ye Lianshan Yan Tao Zhou Yue Zhu Peng Li xihua Zou Wei Pan Center for Information Photonics and Communications School of Information Science and TechnologySouthwest Jiaotong UniversityChengdu 611756China Key Laboratory of Electronic Information Control Southwest China Research Institute of Electronic EquipmentChengdu 610029China Microwave Photonics Research Laboratory School of Electrical Engineering and Computer ScienceUniversity of OttawaOttawaONK1N6N5Canada

We propose and experimentally demonstrate a photonic method for wideband multipath self-interference cancellation using a silicon photonic modulator *** chip generates phase-inverted reference signals by leveraging the opposite phase between optical *** managing amplitude and phase imbalances between self-interference and reference signals,the approach rectifies discrepancies through consistent chip manufacturing and packaging *** photonic multi-dimensional multiplexing,including wavelength and polarization,enables the acquisition of multiple reference *** results show multipath cancellation depths of 2..53 dB and 2..81 dB for bandwidths of 500 MHz and 1 GHz,achieved by superimposing 2.path reference signals.

关键词： microwave photonics multipath self-interference silicon photonics

Range inclusion of operators on non-archimedean Banach space

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Science China mathematics 2010年第12期53卷 3215-3224页

作者： WANG PengHui 1 & ZHANG Xu 2.3 1 school of mathematics, Shandong {2., Jinan 2.0100, China 2.Key Laboratory of Systems and Control, Academy of mathematics and Systems Science, Chinese Academy of Sciences, Beijing 100190, China 3 school of mathematics, Sichuan {2., chengdu 610064, China 1. school of mathematics Shandong University Jinan 250100 China2. Key Laboratory of Systems and Control Academy of Mathematics and Systems Science Chinese Academy of Sciences Beijing 100190 China3. School of Mathematics Sichuan University Chengdu 610064 China

In this paper, we establish some range inclusion theorems for non-archimedean Banach spaces over general valued fields. These theorems provide close relationship among range inclusion, majorization and factorization for bounded linear operators. It is found that these results depend strongly on a continuous extension property, which is always true in the classical archimedean case, but may fail to hold for the non-archimedean setting. Several counterexamples are given to show that our results are sharp in some sense.

关键词： range inclusion majorization factorization non-archimedean Banach space continuous extension property

Single-step-lag OOSM algorithm based on unscented transformation

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Science China(Information Sciences) 2011年第3期54卷 664-673页

作者： CHEN JinGuang 1,2., LI Jie 1 & GAO XinBo 1 1 school of Electronic engineering, Xidian {2., Xi’an 710071, China 2.school of computer Science, Xi’an Polytechnic {2., Xi’an 710048, China 1. school of Electronic engineering Xidian University Xi’an 710071 China2. School of Computer Science Xi’an Polytechnic University Xi’an 710048 China

Aiming at the out-of-sequence measurement (OOSM) problem, the update equations of the nonlinear single-step-lag OOSM are derived based on the existing methods. By introducing the unscented transformation (UT), the covariance between state vector and corresponding measurement vector are computed such that the single-step-lag OOSM can be effectively solved under the nonlinear Gaussian system with nonlinear measurement equation and linear dynamic equation. Furthermore, a single-step-lag OOSM fusion algorithm based on UT is presented to confront the problem of the single-step-lag OOSM in multi-sensor system. The proposed algorithm has some advantages over the EKF A1 based on the extended Kalman filter frame and the optimal method without lags. For example, it can be used when the Jacobian matrix or the Hessian matrix of nonlinear measurement equation is nonexistent; its filtering performance is better; and its complexity has the same order of magnitude as that of the EKF A1 algorithm.

关键词： state estimation nonlinear filtering out-of-sequence measurements unscented transformation data fusion

A Hybrid Genetic Algorithm for Reduct of Attributes in Decision System Based on Rough Set Theory

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Wuhan university Journal of Natural Sciences 2002年第3期7卷 285-289页

作者： Dai Jian\|hua 1,2., Li Yuan\|xiang 1,2.,Liu Qun 3 1. State Key Laboratory of Software engineering, Wuhan university, Wuhan 430072. Hubei,China 2. {2. of computer, Wuhan university, Wuhan 430072. Hubei, China 3. {2. of computer Science, Wuhan university State Key Laboratory of Software Engineering Wuhan Hubei China (GRID:grid.49470.3e) (ISNI:***) Wuhan university School of Computer Wuhan Hubei China (GRID:grid.49470.3e) (ISNI:***) Chongqing university of Posts & Telecommunications School of Computer Science Chongqing China (GRID:grid.411587.e) (ISNI:***)

Knowledge reduction is an important issue when dealing with huge amounts of data. And it has been proved that computing the minimal reduct of decision system is NP-complete. By introducing heuristic information into genetic algorithm, we proposed a heuristic genetic algorithm. In the genetic algorithm, we constructed a new operator to maintaining the classification ability. The experiment shows that our algorithm is efficient and effective for minimal reduct, even for the special example that the simple heuristic algorithm can’t get the right result.

关键词： rough set reduction genetic algorithm heuristic algorithm

Image denoising and deblurring: non-convex regularization, inverse diffusion and shock filter

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Science China(Information Sciences) 2011年第6期54卷 1184-1198页

作者： FU ShuJun 1,2.3 , ZHANG CaiMing 2.& TAI XueCheng 3,4 1 school of mathematics, Shandong {2., Jinan 2.0100, China 2.school of computer Science and Technology, Shandong {2., Jinan 2.0101, China 3 school of Physical and Mathematical Sciences, Nanyang Technological {2., Singapore 639798, Singapore 4 Department of mathematics, {2. of Bergen, Bergen 5008, Norway 1. school of mathematics Shandong University Jinan 250100 China2. School of Computer Science and Technology Shandong University Jinan 250101 China3. School of Physical and Mathematical Sciences Nanyang Technological University Singapore 639798 Singapore4. Department of Mathematics University of Bergen Bergen 5008 Norway

A large number of applications in image processing and computer vision depend on image quality. In this paper, main concerns are image denoising and deblurring simultaneously in a restoration task by three types of methodologies: non-convex regularization, inverse diffusion and shock filter. We discuss their relations in the context of image deblurring: the inverse diffusion implied by the non-convex regularization, and the superior ability of deblurring edge of the shock filter to that of the inverse diffusion, both in 1D and 2. cases. Finally, we propose a region-based adaptive anisotropic diffusion with shock filter method, which shows advantages of deblurring edges, denoising and smoothing contours in experiments, compared with some related methods. Therein an idea of "divide and rule" is introduced.

关键词： image denoising image deblurring non-convex regularization inverse diffusion shock filter adaptive anisotropic diffusion

A new real-time eye tracking based on nonlinear unscented Kalman filter for monitoring driver fatigue

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控制理论与应用（英文版） 2010年第2期8卷 181-188页

作者： Zutao ZHANG 1 , 2., Jiashu ZHANG 2.(1.school of Mechanical engineering, Southwest Jiaotong {2., chengdu Sichuan 610031, China 2.Sichuan Key Lab of Signal and Information Processing, Southwest Jiaotong {2., chengdu Sichuan 610031, China) school of Mechanical engineering Southwest Jiaotong University Chengdu Sichuan China Sichuan Key Lab of Signal and Information Processing Southwest Jiaotong University Chengdu Sichuan China

A new scheme for driver fatigue detection is presented, which is based on the nonlinear unscented Kalman filter and eye tracking. Assuming a probability distribution than to approximate an arbitrary nonlinear function or transformation, eye nonlinear tracking can be achieved using an unscented transformation (UT), which adopts a set of deterministic sigma points to match the posterior probability density function of the eye movement. Driver fatigue can be detected using the percentage of eye closure (PERCLOS) framework in a realistic driving condition after the eye nonlinear tracking. This system was tested adequately in realistic driving environments with subjects of different genders, with/without glasses, in day/night driving, being commercial/noncommercial drivers, in continuous driving time, and under different road conditions. The last experimental results show that the proposed method not only improves the robustness for nonlinear eye tracking, but also can provide more accurate estimation than the traditional Kalman filter.

关键词： Eye tracking Unscented Kalman filter (UKF) Fatigue detection PERCLOS

Relaxed delay-dependent exponential stability condition for a class of neural networks with polytopic uncertainties and distributed delays

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控制理论与应用（英文版） 2011年第2期9卷 302-306页

作者： Jianwei XIA 1,2.Hongbin ZHANG 3 1.school of Automation,Southeast university,Nanjing Jiangsu 2.0096,China 2.school of mathematics Science,Liaocheng university,Liaocheng Shandong 2.2.00,China 3.school of Electronic engineering,university of Electronic Science and Technology,chengdu Sichuan 610054,China school of Automation Southeast University Nanjing Jiangsu China school of mathematics Science Liaocheng University Liaocheng Shandong China school of Electronic engineering University of Electronic Science and Technology Chengdu Sichuan China

The global robust exponential stability of a class of neural networks with polytopic uncertainties and distributed delays is investigated in this ***-dependent Lypaunov-Krasovskii functionals and free-weighting matrices are employed to obtain sufficient condition that guarantee the robust global exponential stability of the equilibrium point of the considered neural *** derived sufficient condition is proposed in terms of a set of relaxed linear matrix inequalities (LMIs),which can be checked easily by recently developed algorithms solving LMIs.A numerical example is given to demonstrate the effectiveness of the proposed criteria.

关键词： Neural networks Polytopic uncertainties Distributed delays Delay-dependent Global robust exponential stability