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Perceptual importance analysis for H.264/AVC bit allocation

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2008年第2期9卷 225-231页

作者： Gui-xu LIN Shi-bao zheng Institute of lmage Comm. ＆ Info. Processing Dept. of Electronic Engineering Shanghai Jiao Tong University Shanghai 200240 China Shanghai Key Laboratory of Digital Media Processing and Transmissions Shanghai Jiao Tong University Shanghai 200240 China

The existing H.264/AVC rate control schemes rarely include the perceptual *** a result,the im-provements in visual quality are hardly comparable to those in peak signal-to-noise ratio(PSNR).In this paper,we propose a perceptual importance analysis scheme to accurately abstract the spatial and temporal perceptual characteristics of video *** we perform bit allocation at macroblock(MB)level by adopting a perceptual mode decision scheme,which adaptively updates the Lagrangian multiplier for mode decision according to the perceptual importance of each *** results show that the proposed scheme can efficiently reduce bit rates without visual quality degradation.

关键词： Visual quality Human visual system Rate control H.264/AVC

BER analysis of MPSK space-time code with differential detection over correlated block-fading Rayleigh channel

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The Journal of China Universities of Posts and Telecommunications 2008年第2期15卷 18-25页

作者： ZOU Yu-long zheng bao-yu Institute of Signal Processing and Transmission Nanjing University of Postsand Telecommunications Nanjing 210003 China

MIMO technology proposed in recent years can effectively combat the multipath fading of wireless channel and can considerably enlarge the channel capacity, which has been investigated widely by researchers. However, its performance analysis over correlated block-fading Rayleigh channel is still an open and challenging objective. In this article, an analytic expression of bit error rate （BER） is presented for multiple phase shift keying （MPSK） space-time code, with differential detection over correlated block-fading Rayleigh channel. Through theoretical analysis of BER, it can be found that the differential space-time scheme without the need for channel state information （CSI） at receiver achieves distinct performance gain compared with the traditional nonspace-time system. And then, the system simulation is complimented to verify the above result, showing that the diversity system based on the differential space-time block coding （DSTBC） outperforms the traditional nonspacetime system with diversity gain in terms of BER. Furthermore, the numerical results also demonstrate that the error floor of the differential space-time system is much lower than that of the differential nonspace-time system.

关键词： differential space-time block code correlated blockfading Rayleigh channel CSI error floor

Distributed Parameter Neural Networks via Adaptive Wavelet

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Journal of Systems Engineering and Electronics 1993年第2期4卷 48-62页

作者： Zhuoer, Shi Licheng, Jiao zheng, bao Xidian Univ Xi'an China

The paper outlines a new neural net (DPNN) for describing brain's action based on one-dimensional cable theory. While the traditional neural network system only finding its character involving time changing (as HNN, BP etc.), the model-DPNNs (Distributed parameter neural networks) are not only the transmitted neurons of time variation, but also the functions of positions by the voltage u(x,t). With the neuroscientific relevance, some bioneural features like intermittent conduction and dendritic spike are fixed well by DPNNs which considered as complicated and adaptive devices contract to the functional elementary units. To find the semi-analytical representations of DPNNs, adaptive wavelets are utilized as new microlocalization tools. While maintaining all advantages of wavelet function, the adaptive wavelet offers a viable alternative learning procedure to the orthogonal least squares method (OLS), adaptive wavelet method develops a fairly general low-cost multiscale method for neural net optimization. In addition, a Lyapunov function method is also used to study the uniform asymptotic stability of DPNNs to support the new theory.

关键词： Brain Neurology Optimization

EFFECTS OF COUPLING AGENTS ON THE CRYSTALLIZATION BEHAVIOR OF PP/T-ZnOw COMPOSITES

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Chinese Journal of Polymer Science 2007年第6期25卷 565-572页

作者： Yong Wang zheng-bao He Zuo-wan Zhou Key Laboratory of Advanced Technologies of Materials Ministry of Education School of Materials Science and Engineering Southwest Jiaotong University Chengdu 610031 China State Key Laboratory of Polymer Materials Engineering （Sichuan University） Chengdu 610065 China

The objectives of this paper are to understand the crystallization behavior of polypropylene （PP） composites with surface modified tetra-needle-shaped zinc oxide whisker （T-ZnOw）. T-ZnOw was surface modified with different coupling agents, such as silane coupling agents （KH-550, KH-560） and titanate coupling agent （NDZ-105）, in order to improve the compatibility between PP and T-ZnOw. DSC and POM were used to characterize the melt and crystallization behavior and the crystalline structures of the composites, respectively. The results show that the surface modified T-ZnOw acts as a nucleating agent of PP crystallization, depending on the coupling agent used for modification. KH-550 and KH-560 have more apparent role in improving the interfacial interaction than NDZ-105 and induce PP crystallization at higher temperature and with smaller spherulites size. The results also suggest that the crystallization behavior depends on not only the content of coupling agent, but also the content of the surface modified T-ZnOw used in the composites.

关键词： PP/T-ZnOw Crystallization behaviour Coupling agent.

A coordinate-transform based FFBP algorithm for high-resolution spotlight SAR imaging

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Science China(Information Sciences) 2015年第2期58卷 31-41页

作者： YANG ZeMin XING MengDao ZHANG Lei bao zheng National Key Lab of Radar Signal Processing Xidian University

This paper proposes a coordinate-transform(CT) implementation for the fast factorized backprojection(FFBP) algorithm(CT-FFBP) to process high-resolution spotlight synthetic aperture radar(SAR)data. Unlike the FFBP utilizing two-dimensional image-domain interpolation for sub-aperture fusion, CT-FFBP finishes the image-projection using CT with the accommodation of chirp-z transform and circular shifting. Without interpolation, CT-FFBP yields enhanced efficiency over the interpolation based FFBP, besides maintaining high precision simultaneously. Both simulation and real-data experiments verifies the efficiency and precision superiorities of the CT-FFBP.

关键词： spotlight synthetic aperture radar(SAR) fast factorized back-projection(FFBP) coordinate-transform(CT)

New statistical model for radar HRRP target recognition

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Journal of Systems Engineering and Electronics 2010年第2期21卷 204-210页

作者： Qingyu Hou Feng Chen Hongwei Liu zheng bao National Lab of Radar Signal Processing Xidian University Xi'an 710071 R R. China

The mixture of factor analyzers （MFA） can accurately describe high resolution range profile （HRRP） statistical charac- teristics. But how to determine the proper number of the models is a problem. This paper develops a variational Bayesian mixture of factor analyzers （VBMFA） model. This procedure can obtain a lower bound on the Bayesian integral using the Jensen＇s inequality. An analytical solution of the Bayesian integral could be obtained by a hypothesis that latent variables in the model are indepen- dent. During computing the parameters of the model, birth-death moves are utilized to determine the optimal number of model au- tomatically. Experimental results for measured data show that the VBMFA method has better recognition performance than FA and MFA method.

关键词： radar automatic target recognition (RATR) high reso- lution range profile (HRRP) variational Bayesian mixtures of factor analyzers (VBMFA) variational Bayesian(VB) mixtures of factor analyzers (MFA).

Property analysis of bistatic forward-looking SAR with arbitrary geometry

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Journal of Systems Engineering and Electronics 2016年第1期27卷 111-127页

作者： Ziqiang Meng Yachao Li Mengdao Xing zheng bao National Laboratory of Radar Signal Processing Xidian University

Bistatic forward-looking synthetic aperture radar（SAR） has many advantages and applications owing to its twodimensional imaging *** could be various imaging configurations because of the geometric flexibility of bistatic platforms,resulting in kinds of models built independently among which there could be some similar even the same motion *** research on such systems in a more comprehensive and general point of view is required to address their difference and *** analysis of bistatic forwardlooking SAR with arbitrary geometry is achieved including stripmap and spotlight modes on airborne platform,missile-borne platform,and hybrid platform of *** is placed on azimuth space variance of some key parameters significantly affecting the subsequent imaging processing,based on which the frequency spectra are further described and compared considering respective features of different platforms for frequency imaging algorithm *** results confirm the effectiveness and correctness of our analysis.

关键词： bistatic forward-looking synthetic aperture radar(SAR) comprehensive research property analysis azimuth space variance.

Rating-protocol optimization for blockchain-enabled hybrid energy trading in smart grids

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Science China(Information Sciences) 2023年第5期66卷 297-298页

作者： zheng bao Changbing TANG Feilong LIN Zhonglong zheng Xinghuo YU College of Mathematics and Computer Science Zhejiang Normal University College of Physics and Electronics Information Engineering Zhejiang Normal University School of Engineering RMIT University

Dear editor,Smart grids, with renewable energy technologies, provide an innovative approach for mitigating the energy crisis caused by the shortage of fossil fuel resources. However, the existing smart grids are confronted with several challenges [1, 2].Specially, the decentralization of resources and the inflexible trading patterns call for a secure infrastructure and an efficient energy management mechanism, respectively.

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Ground moving target detection and location based on SAR images for distributed spaceborne SAR

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Science in China(Series F) 2005年第5期48卷 632-646页

作者： LI Zhenfang bao zheng YANG Fengfeng Key Laboratory for Radar Signal Processing Xidian University Xran 710071 China National University of Defence Technology Changsha 4100731 China

This paper investigates data processing approaches to detect and locate ground moving targets using distributed spaceborne SAR systems with long cross-track baselines. In particular, it investigates the performance of ground moving target detection for two typical satellite formations： Cartwheel and Pendulum. An approach based on SAR images and a space-time adaptive processing （STAP） algorithm is proposed in order to overcome the effects of the ground terrain on the clutter suppression. The key idea of the approach is firstly to reduce the clutter degrees of freedom greatly by using conventional SAR imaging processing. Then the ground terrain clutter within each SAR pixel can be effectively cancelled by using the very limited spatial degrees of freedom. Finally, constant-false-alarm-rate （CFAR） techniques can be used to detect the remaining target SAR pixels after clutter cancellation. An approach to relocate the detected targets is also proposed, which is based on the estimation of the Doppler spectrum shifts of ground moving targets relative to the clutter Doppler spectrum. The proposed approaches in this paper have the advantages of simplicity and high efficiency.

关键词： formation-flying satellites ground moving target indication spaceborne synthetic apertureradar (spaceborne SAR) space-time adaptive processing (STAP) cartwheel pendulum.