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Multi-UAVs Collaborative Path Planning in the Cramped Environment

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IEEE/CAA Journal of Automatica Sinica 2024年第2期11卷 529-538页

作者： Siyuan Feng Linzhi Zeng Jining Liu Yi Yang Wenjie Song School of Automation Beijing Institute of TechnologyNanjing 210039China Nanjing Research institute of electronics Technology Nanjing 210039China Yichang Testing technique Research institute Yichang 443003China IEEE

Due to its flexibility and complementarity, the multiUAVs system is well adapted to complex and cramped workspaces, with great application potential in the search and rescue(SAR) and indoor goods delivery fields. However, safe and effective path planning of multiple unmanned aerial vehicles(UAVs)in the cramped environment is always challenging: conflicts with each other are frequent because of high-density flight paths, collision probability increases because of space constraints, and the search space increases significantly, including time scale, 3D scale and model scale. Thus, this paper proposes a hierarchical collaborative planning framework with a conflict avoidance module at the high level and a path generation module at the low level. The enhanced conflict-base search(ECBS) in our framework is improved to handle the conflicts in the global path planning and avoid the occurrence of local deadlock. And both the collision and kinematic models of UAVs are considered to improve path smoothness and flight safety. Moreover, we specifically designed and published the cramped environment test set containing various unique obstacles to evaluating our framework performance thoroughly. Experiments are carried out relying on Rviz, with multiple flight missions: random, opposite, and staggered, which showed that the proposed method can generate smooth cooperative paths without conflict for at least 60 UAVs in a few *** benchmark and source code are released in https://***/inin-xingtian/multi-UAVs-path-planner.

关键词： Collision avoidance conflict resolution multi-unmanned aerial vehicles(UAVs)system path planning

Dual-band and polarization-insensitive terahertz absorber based on fractal Koch curves

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Chinese Physics B 2014年第5期23卷 594-599页

作者：马岩冰张怀武李元勋王艺程赖伟恩李颉 State Key Laboratory of electronic Films and Integrated Devices University of Electronic Science and Technology of China institute of electronic and Information Engineering University of Electronic Science and Technology of China

We report the design, fabrication, and characterization of a dual-band and polarization-insensitive metamaterial ab-sorber （MA）, which consists of periodically arranged fractal Koch curves acting as the top resonator array and a metallic ground plane separated by a dielectric spacer. Compared with conventional MAs, a more compact size and multi-frequency operation are achieved by using fractal geometry as the unit cell of the MA. Both the effective medium theory and the multi- reflection interference theory are employed to investigate the underlying physical mechanism of the proposed terahertz MA, and results indicate that the latter theory is not suitable for explaining the absorption mechanism in our investigated struc-ture. Two absorption peaks are observed at 0.226 THz and 0.622 THz with absorptivities of 91.3% and 95.6% respectively and good agreements between the full-wave simulation and experimental results are achieved.

关键词： metamaterial absorber terahertz fractal geometry

Dirac spin-gapless semiconductors:promising platforms for massless and dissipationless spintronics and new(quantum) anomalous spin Hall effects

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National Science Review 2017年第2期4卷 252-257页

作者： Xiao-Lin Wang Spintronic and electronic Materials Group Institute for Superconducting and Electronic MaterialsAustralian Institute for Innovative MaterialsUniversity of Wollongong

It is proposed that the new generation of spintronics should be ideally massless and dissipationless for the realization of ultra-fast and ultra-low-power spintronic devices. We demonstrate that the spin-gapless materials with linear energy dispersion are unique materials that can realize these massless and dissipationless states. Furthermore, we propose four new types of spin Hall efects that consist of spin accumulation of equal numbers of electrons and holes having the same or opposite spin polarization at the sample edge in Hall efect measurements, but with vanishing Hall voltage. hese new Hall efects can be classiied as(quantum) anomalous spin Hall efects. he physics for massless and dissipationless spintronics and the new spin Hall efects are presented for spin-gapless semiconductors with either linear or parabolic dispersion. New possible candidates for Dirac-type or parabolic-type spin-gapless semiconductors are proposed in ferromagnetic monolayers of simple oxides with either honeycomb or square latices.

关键词： spintronics spin-gapless materials spin Hall efects

Impaction of Aggregated Network Traffic on Queueing Performance

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Wuhan University Journal of Natural Sciences 2007年第2期12卷 275-278页

作者： RAO Yunhua WEI Cui QIN Ming SUN Lijun ZHAO Cuncheng WANG Zhiguo School of electronic Information Wuhan UniversityWuhan 430072 Hubei China Yichang Testing technique Research institute Yichang 443003 Hubei China

The impaction of aggregated network traffic on queueing system is studied in this paper. It shows that the network traffic stayed in buffer has different impaction on queueing performance when it is aggregated at different scales. And its influence is related not only to traffic parameters but also to system parameter, such as buffer size. The increased buffer size can absorb the effect of short-range dependence （SRD） in network traffic and only the effect of long-range dependence （LRD） is expressed. The queueing length is asymptotic Weibull distribution with increasing buffer size, which is irrespective with the effect of short-range dependence character. Monte-Carlo based simulation confirmed the validity of these results.

关键词： traffic queueing system loss rate buffer

The codes of matter and their applications

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Science Bulletin 2015年第19期60卷 1661-1673页

作者： Xiao-Lin Wang Spintronic and electronic Materials Group Institute for Superconducting and Electronic Materials Australia Institute for Innovative Materials University of Wollongong

The elements in the periodic table are the building blocks used to form substances with different compositions. Nevertheless, it is the properties of substances that are decisive for their existence and practical applications. Searching for new class of materials with exotic properties has always been challenging because of the complexity of both the theoretical and the experimental approaches developed so far. Here, we propose that the three ubiquitous and paramount attributes of all existing matter charge(Q), spin(S) or rotational motion, and linear motion(K) can be used to account for the formation of different types of matter/materials and their properties that have been or will be known to us. The three attributes or original codes can produce six primary codes which can further produce another sixty codes. The physical meanings represented by each code are unlocked. The table consisting of the 60 codes is introduced as the table of properties of codes of matter. We demonstrate that these codes can be used as building blocks to form new properties and new materials. Many new types of quasiparticles and new classes of materials with exotic properties of Q, S and K are predicted. Their possible experimental realizations are proposed. The possible applications of the codes of matter in other fields such as elementary particles, photonics and chemistry are briefly discussed. We know that there should be more new materials and new electronic, spin and photonic states to be discovered, but we do not know what they are. The codes of matter clearly reveal to us how many and what they are and how easily we can recognize what they are. Experimental and theoretical exploration for new forms of matter, new quasiparticles, or new electronic and spin states, or new states of photon or properties of light, as well as macroscopic entities with exotic properties represented by the codes of matter, is imminent.

关键词： New materials New electronic state New method Materials design

Two-dimensional photoelectron momentum distribution of hydrogen in intense laser field

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Chinese Physics B 2011年第11期20卷 183-189页

作者：孙长平赵松峰陈建宏周效信 Key Laboratory of Atomic and Molecular Physics and Functional Materials of Gansu Province College of Physics and Electronic EngineeringNorthwest Normal University Peili College of Engineering and technique Lanzhou City University

Two-dimensional （2D） electron momentum distributions and energy spectra of a hydrogen in an intense laser field are calculated by solving the time-dependent SchrSdinger equation combined with the window-operator technique. Compared with the standard projection technique, the window-operator technique has the advantage that the continuum states of atoms can be avoided in the calculation. We show that the 2D electron momentum distributions and the energy spectra from those two techniques accord quite well with each other if an appropriate energy width is used in the window operator.

关键词： momentum distribution energy spectra time-dependent Schrodinger equation

A Nonparametric Approach to Foreground Detection in Dynamic Backgrounds

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China Communications 2015年第2期12卷 32-39页

作者： LIAO Juan JIANG Dengbiao LI Bo RUAN Yaduan CHEN Qimei institute of electronic Science and Engineering Nanjing

Foreground detection is a fundamental step in visual ***,accurate foreground detection is still a challenging task especially in dynamic *** this paper,we present a nonparametric approach to foreground detection in dynamic *** uses a history of recently pixel values to estimate background ***,the adaptive threshold and spatial coherence are introduced to enhance robustness against false *** results indicate that our approach achieves better performance in dynamic backgrounds compared with several approaches.

关键词： foreground detection dynamic background the decision threshold spatial coherence

A Hardware Trojan Detection Method Based on the Electromagnetic Leakage

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China Communications 2019年第12期16卷 100-110页

作者： Lei Zhang Youheng Dong Jianxin Wang Chaoen Xiao Ding Ding Beijing electronic Science and Technology institute

Hardware Trojan(HT) refers to a special module intentionally implanted into a chip or an electronic system. The module can be exploited by the attacker to achieve destructive functions. Unfortunately the HT is difficult to detecte due to its minimal resource occupation. In order to achieve an accurate detection with high efficiency, a HT detection method based on the electromagnetic leakage of the chip is proposed in this paper. At first, the dimensionality reduction and the feature extraction of the electromagnetic leakage signals in each group(template chip, Trojan-free chip and target chip) were realized by principal component analysis(PCA). Then, the Mahalanobis distances between the template group and the other groups were calculated. Finally, the differences between the Mahalanobis distances and the threshold were compared to determine whether the HT had been implanted into the target chip. In addition, the concept of the HT Detection Quality(HTDQ) was proposed to analyze and compare the performance of different detection methods. Our experiment results indicate that the accuracy of this detection method is 91.93%, and the time consumption is 0.042s in average, which shows a high HTDQ compared with three other methods.

关键词： hardware trojan detection side channel analysis electromagnetic leakage principal component analysis Mahalanobis distance detection quality

Controlled calibration method for laser induced breakdown spectroscopy

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Chinese Optics Letters 2008年第1期6卷 5-8页

作者：汪力张持健冯源 The Intelligence Measure-Control technique Research Center Anhui Normal University institute of Atomic and Molecular Physics Anhui Normal University

Laser induced breakdown spectroscopy （LIBS） is a potential technique for rapid analysis of samples present in solids, gases and liquids. In the last two decades it was an object of extensive studies. Controlled calibration method used to analysis the LIBS spectra is investigated. Compared with the inner calibration and calibration-free （CF） methods, this new method overcomes ＂matrix effect＂, and demonstrates a better ability to cope with the spectra. It is used to analyze natural soil, and errors of the concentration are decreased about 5%. The result shows that the new method is feasible and accurate.

关键词： Atomic physics Calibration Laser applications Molecular physics