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Modeling and analysis of ground target radiation cross section

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Chinese science Bulletin 2008年第9期53卷 1444-1449页

作者： SHI Xiang LOU GuoWei LI XingGuo Shanghai institute of Micro-system and information Technology Chinese Academy of Sciences Shanghai 200050 China research institute of MMW and Light Wave Near-sensing Technology Nanjing University of Science and Technology Nanjing 210094 China

Based on the analysis of the passive millimeter wave (MMW) radiometer detection, the ground target radiation cross section is modeled as the new token for the target MMW radiant characteristics. Its ap- plication and actual testing are discussed and analyzed. The essence of passive MMW stealth is target radiation cross section reduction.

关键词：微波模型模拟辐射交叉断面辐射计

Cluster-Based Saliency-Guided Content-Aware Image Retargeting

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Journal of Electronic science and Technology 2017年第2期15卷 141-146页

作者： Li-Wei Kang Ching-Yu Tseng Chao-Long Jheng Ming-Fang Weng Chao-Yung Hsu Graduate School of Engineering science and Technology and the Department of Computer science and information Engineering MPI Corporation Hsinchu Changing Information Technology Inc.Hsinchu 308 institute for information Industry Taipei 106 automation and Instrumentation System Development Sec. China Steel CorporationKaohsiung 81233

Straightforward image resizing operators without considering image contents （e.g., uniform scaling） cannot usually produce satisfactory results, while content-aware image retargeting aims to arbitrarily change image size while preserving visually prominent features. In this paper, a cluster-based saliency-guided seam carving algorithm for content- aware image retargeting is proposed. To cope with the main drawback of the original seam carving algorithm relying on only gradient-based image importance map, we integrate a gradient-based map and a cluster-based saliency map to generate a more reliable importance map, resulting in better single image retargeting results. Experimental results have demonstrated the efficacy of the proposed algorithm.

关键词： Index Terms--Content-aware image retargeting image resizing multimedia adaptation saliency detection seam carving.

Development of a portable coal rock charge monitoring instrument and its application for rockburst control

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Geohazard Mechanics 2024年第3期2卷 216-224页

作者： Gang Wang Hongrui Zhao Lianpeng Dai Haojun Wang Jinguo Lyu Jianzhuo Zhang School of Environmental Liaoning UniversityShenyang110036China Coal science and Technology Group Shenyang research institute Shenyang110015China institute of Disaster Rock Mechanics Liaoning UniversityShenyang110036China Liaoning Key Laboratory of Mining Environment and Disaster Mechanics Liaoning Technical UniversityFuxin123000China Department of Civil Engineering Monash UniversityVictoria3800Australia School of Mechanics and Engineering Liaoning Technical UniversityFuxin123000China School of Mechanical Engineering Liaoning Technical UniversityFuxin123000China

Effective monitoring techniques and equipment are essential for the prevention and control of coal and rockdynamic disasters such as rockburst. Based on the fact that there is charge generation during deformation andrupture of coal rock body and the charge signals contain a large amount of information about the mechanicalprocess of deformation and rupture of coal rock, the rockburst charge sensing monitoring technology has beenformed. In order to improve the charge sensing technology for monitoring and early warning of rockburst disasters, this paper develops a new generation of portable coal rock charge monitoring instrument on the basis ofthe original instrument and carries out laboratory and underground ﬁeld application. The primary advancementinvolves enhancing the external structure of the sensor and increasing the charge sensing area, which can morecomprehensively capture the charge signals from the loaded rupture of the coal rock body. The overall structure ofthe data acquisition instrument has been improved, the monitoring channels have been increased, and thefunction of displaying the monitoring data curve has been added, so that the coal and rock body force status canbe grasped in time. The results of the experimental study show that the abnormal charge signals can be monitoredduring the rupture process of rock samples under loading, and the monitored charge signals are in good agreement with the sudden change of stress in the rock samples and the formation of crack extension. There is aprecursor charge signal before the stress mutation, and the larger the loading rate is, the earlier the precursorcharge signal appears. The charge monitoring instrument can monitor the charge signal of the coal seam roadwayunder strong mining pressure. In the zone of elevated overburden pressure, the amount of induced charge is large,and anomalously high value charge signals can be monitored when a coal shot occurs. The change trend of thecharge at different measuring point

关键词： Rockburst Charge monitoring instrument Man-machine dialogue Stress distribution Monitor

Multiple Impact Factor Based Accuracy Analysis for Power Quality Disturbance Detection

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CSEE Journal of Power and Energy Systems 2023年第1期9卷 88-99页

作者： Zijing Yang Haochen Hua Junwei Cao Electromechanical Engineering Beijing Institute of Graphic CommunicationBeijing 102600China College of Energy and Electrical Engineering Hohai University 211100China Beijing National research Center for information science and Technology Tsinghua UniversityBeijing 100084China

Nowadays,power quality problems are affecting people’s daily life and production *** an aim to improve disturbance detection accuracy,a novel analysis approach,based on multiple impact factors,is proposed in this ***,a multiple impact factors analysis is implemented in which two perspectives,i.e.,the wavelet analysis and disturbance features are simultaneously *** key factors,including wavelet function,wavelet decomposition level,redundant algorithm,event type and disturbance intensity,and start and end moment of disturbance,have been ***,an impact factor based accuracy analysis algorithm is proposed,through which each factor’s potential impact on disturbance location accuracy is *** transforms,i.e.,the classic wavelet,lifting wavelet and redundant lifting wavelet are employed,and their superiority on disturbance location accuracy is ***,simulations are conducted for *** the proposed method,the wavelet based parameters can be validly selected in order to accurately detect power quality disturbance.

关键词： Disturbance location accuracy impact factors power quality wavelet analysis

Optimal Relay Assignment and Power Allocation for Cooperative Communications

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Journal of Computer science & Technology 2013年第2期28卷 343-356页

作者：谢鲲曹建农文吉刚 School of information science and Engineering Hunan University Department of Computing Hong Kong Polytechnic University institute of Computing Technology Chinese Academy of Sciences

Cooperative communication for wireless networks has gained a lot of recent interest due to its ability to mitigate fading with exploration of spatial diversity. In this paper, we study a joint optimization problem of jointly considering transmission mode selection, relay assignment and power allocation to maximize the capacity of the network through cooperative wireless communications. This problem is much more challenging than relay assignment considered in literature work which simply targets to maximize the transmission capacity for a single transmission pair. We formulate the problem as a variation of the maximum weight matching problem where the weight is a function over power values which must meet power constraints （VMWMC）. Although VMWMC is a non-convex problem whose complexity increases exponentially with the number of relay nodes, we show that the duality gap of VMWMC is virtual zero. Based on this result, we propose a solution using Lagrange dual decomposition to reduce the computation complexity. We do simulations to evaluate the performance of the proposed solution. The results show that our solution can achieve maximum network capacity with much less computation time compared with exhaustive search, and our solution outperforms existing sub-optimal solutions that can only achieve much lower network capacity.

关键词： cooperative communication network capacity dual decomposition relay assignment power allocation

Performance analysis of a low-complexity nonorthogonal multiple access scheme in visible light communication downlinks using pulse modulations

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Intelligent and Converged Networks 2021年第1期2卷 50-65页

作者： Jian Song Tian Cao Hongming Zhang Beijing National research Center for information science and Technology(BNRist) Department of Electronic EngineeringTsinghua UniversityBeijing 100084China Key Laboratory of Digital TV System of Guangdong Province and Shenzhen City Research Institute of Tsinghua University in ShenzhenShenzhen 518057China Beijing National research Center for information science and Technology(BNRist) and Department of Electronic EngineeringTsinghua UniversityBeijing 100084China

Although Successive Interference Cancellation(SIC)decoding is widely adopted in Nonorthogonal Multiple Access(NOMA)schemes for the recovery of user data at acceptable complexity,the imperfect SIC would cause Error Propagation(EP),which can severely degrade system *** this work,we propose an SIC-free NOMA scheme in pulse modulation based Visible Light Communication(VLC)downlinks,including two types of users with different data rate *** bit-rate users adopt on-off keying,whereas high bit-rate ones use Multiple Pulse Position Modulation(MPPM).The soft decision decoding scheme is exploited by high bit-rate users to decode MPPM signals,which could fundamentally eliminate the detrimental effect of EP;the scheme is also easier and faster to execute compared with the conventional SIC decoding *** of the symbol error rate and achievable data rate for two types of users are *** of the Monte Carlo simulation are provided to confirm the correctness of theoretical results.

关键词： visible light communication nonorthogonal multiple access error propagation on-off keying multiple pulse position modulation symbol error rate achievable data rate

Reducing the Upper Bound Delay by Optimizing Bank-to-Core Mapping

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Journal of Computer science & Technology 2016年第6期31卷 1179-1193页

作者： Ji-Zan Zhang Zhi-Min Gu Ming-Quan Zhang School of Computer science and Technology Beijing Institute of Technology Beijing 100081 China School of Mathematics and information Ludong University Yantai 264025 China

Nowadays, inter-task interferences are the main difficulty in analyzing the timing behavior of multicores. The timing predictable embedded multicore architecture MERASA, which allows safe worst-case execution time （WCET） estimations, has emerged as an attractive solution. In the architecture, WCET can be estimated by the upper bound delay （UBD） which can be bounded by the interference-aware bus arbiter （IABA） and the dynamic cache partitioning such as columnization or bankization. However, this architecture faces a dilemma between decreasing UBD and efficient shared cache utilization. To obtain tighter WCET estimation, we propose a novel approach that reduces UBD by optimizing bank-to-core mapping on the multicore system with IABA and the two-level partitioned cache. For this, we first present a new UBD computation model based on the analysis of inter-task interference delay, and then put forward the core-sequence optimization method of bank-to-core mapping and the optimizing algorithms with the minimum UBD. Experimental results demonstrate that our approach can reduce WCET from 4% to 37%.

关键词： multicore hard real-time task bank-to-core mapping upper bound delay optimization

Relationship between Remotely Sensed Vegetation Change and Fracture Zones Induced by the 2008 Wenchuan Earthquake, China

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Journal of Earth science 2013年第2期24卷 282-296页

作者：王玲田兵伟 Alaa Masoud Katsuaki Koike New frontier sciences Graduate School of Science and Technology Kumamoto University Chengdu institute of Biology Chinese Academy of Sciences Department of Urban Management Graduate School of Engineering Kyoto University Geology Department Faculty of Science Tanta University

The Wenchuan earthquake triggered cascading disasters of landslides and debris flows that caused severe vegetation damage. Fracture zones can affect geodynamics and spatial pattern of vegetation damage. A segment tracing algorithm method was applied for identifying the regional fracture system through lineament extractions from a shaded digital elevation model with 25 m mesh for southern Wenchuan. Remote sensing and geographic information system techniques were used to analyze the spatiotemporal vegetation pattern. The relationship between vegetation type identified from satellite images and lineament density was used to characterize the distribution patterns of each vegetation type according to fracture zones. Broad-leaved forest, mixed forest, and farmland persist in areas with moderate lineament density. Deciduous broad-leaved and coniferous forest persists in less frac- tured areas. Shrub and meadow seem to be relatively evenly distributed across all lineament ***, farmland, and shrub persist in the fractured areas. Changes of spatial structure and correlation between vegetation patterns before and after the earthquake were examined using semivariogram analysis of normalized difference vegetation indices derived from Landsat enhanced thematic mapper images. The sill values of the semivariograms show that the spatial heterogeneity of vegetation covers increased after the earthquake. Moreover, the anisotropic behaviors of the semivariograms coincide with the vegetation changes due to the strikes of fracture zones.

关键词： fracture zone vegetation pattern lineament remote sensing geostatistics

Thermodynamics of the System of Massive Dirac Fermions in a Uniform Magnetic Field

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Chinese Physics Letters 2021年第9期38卷 22-29页

作者： Ren-Hong Fang Ren-Da Dong De-Fu Hou Bao-Dong Sun Key Laboratory of Particle Physics and Particle Irradiation(MOE) Institute of Frontier and Interdisciplinary ScienceShandong UniversityQingdao 266237China institute of Particle Physics and Key Laboratory of Quark and Lepton Physics(MOS) Central China Normal UniversityWuhan 430079China

We construct the grand partition function of the system of massive Dirac fermions in a uniform magnetic field from Landau levels,through which all thermodynamic quantities can be *** use of the Abel–Plana formula,these thermodynamic quantities can be expanded as power series with respect to the dimensionless variable𝑏b=2eB/T^(2).The zero-field magnetic susceptibility is expanded at zero mass,and the leading order term is *** also calculate scalar,vector current,axial vector current and energy-momentum tensor of the system through ensemble average *** correction to chiral separation effect is *** massless chiral fermions,our results recover the chiral magnetic effect for right-and left-handed fermions,as well as chiral separation effect.

关键词： chiral Dirac expanded