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Communications in Theoretical Physics 2022年第11期74卷 170-179页

作者： Xianwen Zhou Yiping Xu Yuhui Li Shubo Cheng Zao Yi Guohui Xiao Ziyi Wang Zhanyu Chen School of Physics and Optoelectronic Engineering Yangtze UniversityJingzhou 434023China Joint Laboratory for Extreme Conditions Matter Properties Southwest University of Science and TechnologyMianyang 621010China Jiangxi Province Key Laboratory of Optoelectronics and Communications Jiangxi Science and Technology Normal UniversityNanchang 330038China

We propose a novel bilayer graphene terahertz metamaterial composed of double graphene ribbons and double graphene rings to excite a dynamically adjustable triple plasma-induced transparency(PIT)effect.The coupled mode theory(CMT)is used to explain the PIT phenomenon,and the results of the CMT and the finite-difference time-domain simulation show high matching degree.By adjusting the Fermi levels of graphene,we have realized a pentafrequency asynchronous optical switch.The performance of this switch,which is mainly manifested in the maximum modulation depth(MD=99.97%)and the minimum insertion loss(IL=0.33 dB),is excellent.In addition,we have studied the slow-light effect of this triple-PIT and found that when the Fermi level of graphene reaches 1.2 eV,the time delay can reach 0.848ps.Therefore,this metamaterial provides a foundation for the research of multi-frequency optical switches and excellent slow-light devices in the terahertz band.

关键词： plasma-induced transparency coupled mode theory optical switch slow-light effect

Intelligent computing budget allocation for on-road tra jectory planning based on candidate curves

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Frontiers of Information Technology & Electronic Engineering 2016年第6期17卷 553-565页

作者： Xiao-xin FU Yong-heng JIANG De-xian HUANG Jing-chun WANG Kai-sheng HUANG Department of Automation Tsinghua University Department of Automotive Engineering Tsinghua University

In this paper, on-road trajectory planning is solved by introducing intelligent computing budget allocation(ICBA) into a candidate-curve-based planning algorithm, namely, ordinal-optimization-based differential evolution(OODE). The proposed algorithm is named IOODE with ‘I' representing ICBA. OODE plans the trajectory in two parts: trajectory curve and acceleration profile. The best trajectory curve is picked from a set of candidate curves, where each curve is evaluated by solving a subproblem with the differential evolution(DE) algorithm. The more iterations DE performs, the more accurate the evaluation will become. Thus, we intelligently allocate the iterations to individual curves so as to reduce the total number of iterations performed. Meanwhile, the selected best curve is ensured to be one of the truly top curves with a high enough probability. Simulation results show that IOODE is 20% faster than OODE while maintaining the same performance in terms of solution quality. The computing budget allocation framework presented in this paper can also be used to enhance the efficiency of other candidate-curve-based planning methods.

关键词：轨迹曲线轨迹规划智能计算分配预算道路规划算法迭代次数

Learning Bayesian networks using genetic algorithm

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Journal of Systems Engineering and Electronics 2007年第1期18卷 142-147页

作者： Chen Fei Wang Xiufeng Rao Yimei Coll. of Information Technical science Nankal Univ. Tianjin 300071 P. R. China

A new method to evaluate the fitness of the Bayesian networks according to the observed data is provided. The main advantage of this criterion is that it is suitable for both the complete and incomplete cases while the others not. Moreover it facilitates the computation greatly. In order to reduce the search space, the notation of equivalent class proposed by David Chickering is adopted. Instead of using the method directly, the novel criterion, variable ordering, and equivalent class are combined,moreover the proposed mthod avoids some problems caused by the previous one. Later, the genetic algorithm which allows global convergence, lack in the most of the methods searching for Bayesian network is applied to search for a good model in thisspace. To speed up the convergence, the genetic algorithm is combined with the greedy algorithm. Finally, the simulation shows the validity of the proposed approach.

关键词： Bayesian networks Genetic algorithm Structure learning Equivalent class

Study on the Hungarian algorithm for the maximum likelihood data association problem

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Journal of Systems Engineering and Electronics 2007年第1期18卷 27-32页

作者： Wang Jianguo He Peikun Cao Wei The Second Academy of china Aerospace science & Industry Corp. Beijing 100854 P. R. China Dept. of Electronic Engineering Beijing Inst. of Technology Beijing 100081 P. R. China

A specialized Hungarian algorithm was developed here for the maximum likelihood data association problem with two implementation versions due to presence of false alarms and missed detections. The maximum likelihood data association problem is formulated as a bipartite weighted matching problem. Its duality and the optimality conditions are given. The Hungarian algorithm with its computational steps, data structure and computational complexity is presented. The two implementation versions, Hungarian forest （HF） algorithm and Hungarian tree （HT） algorithm, and their combination with the naYve auction initialization are discussed. The computational results show that HT algorithm is slightly faster than HF algorithm and they are both superior to the classic Munkres algorithm.

关键词： Tracking Data association Linear programming Hungarian algorithm

An efficient and coordinated mapping algorithm in virtualized SDN networks

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Frontiers of Information Technology & Electronic Engineering 2016年第7期17卷 701-716页

作者： Shui-qing GONG Jing CHEN Qiao-yan KANG Qing-wei MENG Qing-chao ZHU Si-yi ZHAO College of Information and Navigation Air Force Engineering University

Software-defined networking(SDN) enables the network virtualization through SDN hypervisors to share the underlying physical SDN network among multiple logically isolated virtual SDN networks(v SDNs),each with its own controller.The v SDN embedding,which refers to mapping a number of v SDNs to the same substrate SDN network,is a key problem in the SDN virtualization environment.However,due to the distinctions of the SDN,such as the logically centralized controller and different virtualization technologies,most of the existing embedding algorithms cannot be applied directly to SDN virtualization.In this paper,we consider controller placement and virtual network embedding as a joint vS DN embedding problem,and formulate it into an integer linear programming with objectives of minimizing the embedding cost and the controller-to-switch delay for each v SDN.Moreover,we propose a novel online vS DN embedding algorithm called CO-v SDNE,which consists of a node mapping stage and a link mapping stage.In the node mapping stage,CO-vS DNE maps the controller and the virtual nodes to the substrate nodes on the basis of the controller-to-switch delay and takes into account the subsequent link mapping at the same time.In the link mapping stage,CO-v SDNE adopts the k-shortest path algorithm to map the virtual links.The evaluation results with simulation and Mininet emulation show that the proposed CO-v SDNE not only significantly increases the long-term revenue to the cost ratio and acceptance ratio while guaranteeing low average and maximum controller-to-switch delay,but also achieves good v SDN performance in terms of end-to-end delay and throughput.

关键词： Software-defined networking(SDN) Network virtualization Controller placement Virtual network embedding Coordination

Bacterial Community Structure in a Mollisol Under Long-Term natural Restoration, Cropping, and Bare Fallow History Estimated by PCR-DGGE

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Pedosphere 2009年第2期19卷 156-165页

作者： WANG Guang-Hua JIN Jian LIU Jun-Jie CHEN Xue-Li LIU Ju-Dong LIU Xiao-Bing Key Laboratory of Black Soil Ecology Northeast Institute of Geography and Agroecology Chinese Academy of Sciences Harbin 150081 China

Soil microbial biomass and community structures are commonly used as indicators for soil quality and fertility. A investigation was performed to study the effects of long-term natural restoration, cropping, and bare fallow managements on the soil microbial biomass and bacterial community structures in depths of 0–10, 20–30, and 40–50 cm in a black soil (Mollisol). Microbial biomass was estimated from chloroform fumigation-extraction, and bacterial community structures were determined by analysis of 16S rDNA using polymerase chain reaction-denaturing gradient gel electrophoresis (PCR- DGGE). Experimental results showed that microbial biomass significantly declined with soil depth in the managements of restoration and cropping, but not in the bare fallow. DGGE profiles indicated that the band number in top 0–10 cm soils was less than that in depth of 20–30 or 40–50 cm. These suggested that the microbial population was high but the bacterial community structure was simple in the topsoil. Cluster and principle component analysis based on DGGE banding patterns showed that the bacterial community structure was a?ected by soil depth more primarily than by managements, and the succession of bacterial community as increase of soil depth has a similar tendency in the three managements. Fourteen predominating DGGE bands were excised and sequenced, in which 6 bands were identified as the taxa of Verrucomicrobia, 2 bands as Actinobacteria, 2 bands as α-Proteobacteria, and the other 4 bands as δ-Proteobacteria, Acidobacteria, Nitrospira, and unclassified bacteria. In addition, the sequences of 11 DGGE bands were closely related to uncultured bacteria. Thus, the bacterial community structure in black soil was stable, and the predominating bacterial groups were uncultured.

关键词：细菌群体群落结构 DGGE PCR 自然修复种植估计土壤微生物量

Combined indirect and direct method for adaptive fuzzy output feedback control of nonlinear system

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Journal of Systems Engineering and Electronics 2007年第1期18卷 120-124页

作者： Ding Quanxin Chen Haitong Jiang Changsheng Chen Zongji Coll. of Automation Engineering Beijing Univ. of Aeronautics & Astronautics Beijing 100083 P. R. China Coll. of Automation Engineering Nanjing Univ. of Aeronautics & Astronautics Nanjing 210016 P. R. China

A novel control method for a general class of nonlinear systems using fuzzy logic systems （FLSs） is presertted. Indirect and direct methods are combined to design the adaptive fuzzy output feedback controller and a high-gain observer is used to estimate the derivatives of the system output. The closed-loop system is proven to be semiglobally uniformly ultimately bounded. In addition, it is shown that if the approximation accuracy of the fuzzy logic system is high enough and the observer gain is chosen sufficiently large, an arbitrarily small tracking error can be achieved. Simulation results verify the effectiveness of the newly designed scheme and the theoretical discussion.

关键词： Nonlinear control systems Non-affine Combined indirect and direct method Adaptive fuzzy controller High-gain observer （HGO）

Low overhead design-for-testability for scan-based delay fault testing

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Journal of Systems Engineering and Electronics 2007年第1期18卷 40-44页

作者： Yang Decai Chen Guangju Xie Yongle Coll. of Automation Engineering Univ. of Electronic Science and Technology Chengdu 610054 P. R. China

An efficient design-for-testability （DFT） technique is proposed to achieve low overhead for scan-based delay fault testing. Existing techniques for delay test such as skewed-load or broadside make the test generation process complex and produce lower coverage for scan-based designs as compared with non-scan designs, whereas techniques such as enhanced-scan test can make the test easy but need an extra holding latch to add substantial hardware overhead. A new tri-state holding logic is presented to replace the common holding latch in enhanced-scan test to get a substantial low hardware overhead. This scheme can achieve low delay overhead by avoiding the holding latch on the critical timing scan path. What＇s more, this method can also keep the state and signal activity in the combinational circuit from the scan during data scan-in operation to reduce the power dissipation. Experiment results on a set of ISCAS89 benchmarks show the efficiency of the proposed scheme.

关键词： Delay fault testing Design for testability Enhanced scan

Study of detection performance of passive bistatic radars based on FM broadcast

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Journal of Systems Engineering and Electronics 2007年第1期18卷 22-26页

作者： Shan Tao Tao Ran Wang Yue Zhou Siyong Dept. of Electronic Engineering Beijing Inst. of Technology Beijing 100081 P. R. China

The passive bistatic radar based on the FM broadcast has inherent superiority with respect to its survivability. In this article, the ambiguity function （AF） and the cross ambiguity function （CAF） of the FM radio signal are analyzed and illustrated. The Kolmogorov Smirnov （K-S） test verifies that the amplitude probability density function of the CAF side lobes is exponential; the distribution of the target is also deduced. Finally, the detection performance of the passive radar is studied, and the result shows that this new type bistatic radar has favorable detection capability.

关键词： Bistatic radar Ambiguity function Cross ambiguity function Probability density function （PDF）

Stochastic stabilization analysis of networked control systems

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Journal of Systems Engineering and Electronics 2007年第1期18卷 137-141页

作者： Ma Changlin Fang Huajing Dept. of Computer science Central China Normal Univ. Wuhan 430079 P. R. China Dept. of Control science and Engineering Huazhong Univ. of Science and Technology Wuhan 430074 P. R. China

Considering the stochastic delay problems existing in networked control systems, a new control mode is proposed for networked control systems whose delay is longer than a sampling period. Under the control mode, the mathematical model of such a system is established. A stochastic stabilization condition for the system is given. The maximum delay can be derived from the stabilization condition.

关键词： Networked control system Asymptotically stable Maximum delay