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On the Probability Density Function of the Real and Imaginary Parts in WFRFT Signals

China Communications 2016年第9期13卷 44-52页

作者： Xiaolu Wang Lin Mei Zhenduo Wang Naitong Zhang Communications research center School of Electronics and Information EngineeringHarbin Institute Technology

Recently a Hybrid Carrier （HC） scheme based on Weighted-type Fractional Fourier Transform （WFRFT） was proposed and developed, which contains Single Carrier （SC） and Multi-Carrier （MC） synergetie transmission. The wide interest is primarily due to its appealing characteristics, such as the robust performances in different types of selective fading channels and a great deal of potential for secure communications. According to the literatures, the HC signal and SC or MC signal probability distributions are different. In particular, some benefits of this HC scheme are brought by the quasi-Gaussian distribution of WFRFT signals. However, until now researchers have only presented statistic properties through computer simulations, and the accurate expressions of signals are not derived yet. In this paper, we derive the accu- rate and rigorously established closed-form expressions of Probability Density Function （PDF） of WFRFT signal real and imaginary parts with a large number of QPSK subcarriers, and this PDF can describe the behavior of data modulated by WFRFT, avoiding the complex computation for extensive computer simulations. Furthermore, the components of PDF expression are described and analyzed, and it is revealed that the tendency of signal quasi-Gaussian changes with the increasing of the parameter a （a in （0,1]）. To validate the analytical results, extensive simulations have been conducted, showing a very good match between the analytical results and the real situations. The contribution of this paper may be useful to deduce the closed form expressions of Bit Error Ratio （BER）, the Complementary Cumulative Distribution Function （CCDF） of Peak to Average Power Ratio （PAPR）, and other analytical studies which adopt the PDF.

关键词： weighted-type fractional Fourier transform probability density function single carrier multi-carrier hybrid carrier

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A New Algorithm for Literature Recommendation Based on a Bibliographic Heterogeneous information Network

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Chinese Journal of Electronics 2018年第4期27卷 761-767页

作者： LI Linna WANG Lijun JIANG Xueqin HAN Hongqi ZHAI Yun Institute of Scientific and Technical information of China E-Government research center Chinese Academy of Governance

A literature recommendation algorithm based on a heterogeneous information network is proposed. The proposed algorithm can process different types of semantic information and implicit feedback. The experimental results show that the proposed algorithm can provide more effective recommendations than those algorithms without employing these semantic information and implicit feedback.

关键词： Literature recommendation algorithm Heterogeneous information network Meta-path Classification Bayesian ranking

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Ob ject Tracking with Dual Field-of-view Switching in Aerial Videos

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International Journal of Automation and computing 2016年第6期13卷 565-573页

作者： Yi Song Shu-Xiao Li Cheng-Fei Zhu Hong-Xing Chang The Integrated information System research center Institute of AutomationChinese Academy of Science

Visual object tracking plays an important role in intelligent aerial surveillance by unmanned aerial vehicles（UAV）. In ordinary applications, aerial videos are captured by cameras with a fixed-focus lens or a zoom lens, for which the field-of-view（FOV）of the camera is fixed or smoothly changed. In this paper, a special application of the visual tracking in aerial videos captured by the dual FOV camera is introduced, which is different from ordinary applications since the camera quickly switches its FOV during the capturing. Firstly, the tracking process with the dual FOV camera is analyzed, and a conclusion is made that the critical part for the whole process depends on the accurate tracking of the target at the moment of FOV switching. Then, a cascade mean shift tracker is proposed to deal with the target tracking under FOV switching. The tracker utilizes kernels with multiple bandwidths to execute mean shift locating, which is able to deal with the abrupt motion of the target caused by FOV switching. The target is represented by the background weighted histogram to make it well distinguished from the background, and a modification is made to the weight value in the mean shift process to accelerate the convergence of the tracker. Experimental results show that our tracker presents a good performance on both accuracy and efficiency for the tracking. To the best of our knowledge, this paper is the first attempt to apply a visual object tracking method to the situation where the FOV of the camera switches in aerial videos.

关键词： tracker camera histogram captured surveillance switching intelligent cascade Tracking quickly

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A syntactic path-based hybrid neural network for negation scope detection

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Frontiers of Computer Science 2020年第1期14卷 84-94页

作者： Lydia LAZIB Bing QIN Yanyan ZHAO Weinan ZHANG Ting LIU research center for Social Computing and information Retrieval Harbin Institute of TechnologyHarbin 150001China

The automatic detection of negation is a crucial task in a wide-range of natural language processing(NLP)applications,including medical data mining,relation extraction,question answering,and sentiment *** this paper,we present a syntactic path-based hybrid neural network architecture,a novel approach to identify the scope of negation in a *** hybrid architecture has the particularity to capture salient information to determine whether a token is in the scope or not,without relying on any human *** approach combines a bidirectional long shortterm memory(Bi-LSTM)network and a convolutional neural network(CNN).The CNN model captures relevant syntactic features between the token and the cue within the shortest syntactic path in both constituency and dependency parse *** Bi-LSTM learns the context representation along the sentence in both forward and backward *** evaluate our model on the Bioscope corpus,and get 90.82%F-score(78.31%PCS)on the abstract sub-corpus,outperforming features-dependent approaches.

关键词： natural language processing negation scope detection convolutional neural network recurrent neural network syntactic path

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Dynamic Modeling and Investigation of Maneuver Characteristics of A Deep-Sea Manned Submarine Vehicle

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China Ocean Engineering 2009年第3期23卷 505-516页

作者：谢俊元须文波张华徐鹏飞崔维成 College of information Engineering Jiangnan University China Ship Scientific research center

A deep-sea Manned Submarine Vehicle （MSV） is usually required to move at a low forward speed and a low rotational speed when it executes investigation tasks. In this condition, the motion is in large drift angles, and the maneuverability hydrodynamic forces cannot be expressed properly in the conventional mathematical model of submersible motion. In this paper, firstly, a general equation of MSV with six-freedom motion is presented, and the numerical simulation of descent/ascent motion and helix motion is conducted to reveal the general maneuver characteristics of MSV. Secondly, according to the data of captive model tests of large drift angles of MSV, the regression analysis of position hydrodynamic forces and rotation hydrodynamic forces is carried out, and the results of regression analysis of maneuverability hydrody- namic characteristics are analyzed to reveal the special maneuver characteristics. Thirdly, a special new mathematical model of MSV with the whole range of drift angles motion is presented, which can be used to predict hydrodynamic performance of motion in the 0° - 180° range of drift angles. The results are applied to the design of maneuverability hydrodynamic forces, development of control system and simulator of a practical MSV.

关键词： Manned Submarine Vehicle ( MSV) dynamic and kinematic modeling large drift angle numerical simulation

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Phase Noise Monitor and Reduction by Parametric Saturation Approach in Phase Modulation Systems

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Chinese Physics Letters 2011年第2期28卷 97-100页

作者： XU Ming ZHOU Zhen PU Xiao JI Jian-Hua YANG Shu-Wen Advanced Technology research center of information Engineer Academy in Shenzhen University Shenzhen 518060

Nonlinear phase noise(NLPN)is investigated theoretically and numerically to be mitigated by parametric saturation approach in DPSK *** nonlinear propagation equation that incorporates the phase of linear and nonlinear is analyzed with parametric saturation processing(PSP).The NLPN is picked and monitored with the power change factors in the DPSK *** process can be realized by an optical PSP limiter and a novel apparatus with feedback *** monitor range of phase noise is 0°-90°,which may be reduced to 0°-45°if the monitor factor is about the Stockes wave but not an anti-Stockes *** is shown that DPSK signal performance can be improved based on the parametric saturation approach.

关键词： DPSK saturation parametric

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Calcium-permeable AMPA receptors:an underestimated pharmacological target for the therapy of brain pathologies

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Neural Regeneration research 2023年第12期18卷 2669-2670页

作者： Sergei G.Gaidin Artem M.Kosenkov Federal research center“Pushchino Scientific center for biological research of the Russian Academy of Sciences” Institute of Cell Biophysics of the Russian Academy of SciencesPushchinoRussia

Excitotoxicity resulting from the accumulation of extracellular glutamate(the main excitatory neurotransmitter in the brain)is one of the main causes of neuronal death in various brain pathologies,including traumatic brain injury,epilepsy,stroke,and a number of neurodegenerative diseases such as Parkinson's and Alzheimer's diseases.

关键词： epilepsy diseases Alzheimer

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Heterogeneity Analysis of Cucumber Canopy in the Solar Greenhouse

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Journal of Integrative Agriculture 2014年第12期13卷 2645-2655页

作者： QIAN Ting-ting LU Sheng-lian ZHAO Chun-jiang GUO Xin-yu WEN Wei-liang DU jian-jun Shanghai Jiao Tong University Beijing research center for information Technology in Agriculture

Detailed analysis of canopy structural heterogeneity is an essential step in conducting parameters for a canopy structural model. This paper aims to analyze the structural heterogeneity of a cucumber （Cucumis sativus L.） canopy by means of analyzing leaf distribution in a greenhouse environment with natural sunlight and also to assess the effect of structural canopy heterogeneity on light interception and photosynthesis. Two experiments and four measurements were carried out in autumn 2011 and spring 2012. A static virtual three-dimensional （3D） canopy structure was reconstructed using a 3D digitizing method. The diurnal variation of photosynthesis rate was measured using CIRAS-2 photosynthesis system. The results showed that, leaf azimuth as tested with the Rayleigh-test was homogeneous at vine tip over stage but turned heterogeneous at fruit harvest stage. After eliminating the inlfuence of the environment on the azimuth using the von Mises-Fisher method, the angle between two successive leaves was 144°;at the same time, a rule for the azimuth distribution in the canopy was established, stating that the azimuth distribution in cucumber followed a law which was positive spin and anti-spin. Leaf elevation angle of south-oriented leaves was on average 13.8° higher than that of north-oriented leaves. The horizontal distribution of light interception and photosynthesis differed signiifcantly between differently oriented leaves. East-and west-oriented leaves exhibited the highest photosynthetic rate. In conclusion, detailed analysis of canopy structural heterogeneity in this study indicated that leaf azimuth and elevation angle were heterogeneous in cucumber canopy and they should be explicitly described as they have a great impact both on light distribution and photosynthesis.

关键词： heterogeneity inclination leaf azimuth light interception photosynthesis

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Application of BeiDou navigation satellite system in emergency rescue of natural hazards: a case study for field geological survey of Qinghai−Tibet plateau

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Geo-Spatial information Science 2018年第4期21卷 294-301页

作者： Ming Hao Jianlong Zhang Ruiqing Niu Changrong Deng Hong Liang National Engineering research center for Geographic information System WuhanChina Chengdu center of China Geological Survey ChengduChina

In recent years,geological and mineral resources exploration in China has expanded to deep hinterland of the Qinghai−Tibet Plateau and other regions with complex geological *** special natural conditions of Qinghai−Tibet Plateau determine the characteristics of“life-forbidden zone”that is characterized by alpine hypoxia,changeable weather,complex road conditions,and beast *** particular,the work in wild depopulated zones with severe environment and poor communications imposes serious threats to the life safety of geological ***,how to guarantee the safety of geological personnel working on the Qinghai−Tibet Plateau and how to reduce or even avoid casualty of geological personnel have currently become the urgent *** this study,an emergency rescue information system for field geological survey is constructed based on BeiDou Navigation Satellite System.A case study of emergency rescue has been conducted in the depopulated zone of the Qinghai−Tibet Plateau and good effects have been achieved,providing security assurance for personnel engaged in field geological survey on the Qinghai−Tibet Plateau and technical support for the emergency rescue in case of natural hazards on the Qinghai−Tibet *** BeiDou Navigation Satellite System(BDS)can be effectively used to locate and communicate in the emergency rescue for rigorous Geological survey task where there is no network signal for the mobile phone,and the emergency rescue guarantee system is independent,reliable,and relatively *** application value of BDS is demonstrated in the geological field.

关键词： BeiDou navigation satellite system(BDS) natural hazard emergency rescue Qinghai−Tibet plateau

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Lattice-based access authentication scheme for quantum communication networks

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Science China(information Sciences) 2024年第12期67卷 311-317页

作者： Min WANG Gui-Lu LONG Beijing Academy of Quantum information Sciences State Key Laboratory of Low-dimensional Quantum Physics and Department of Physics Tsinghua University Frontier Science center for Quantum information Beijing National research center for information Science and Technology

Access authentication scheme plays a foundational role in ensuring the security of communication networks. However, an access authentication scheme with high security and efficiency is still lacking in quantum communication networks. In this paper, we propose a lattice-based access authentication scheme for quantum communication networks in the manner of real-time interaction with the network control center,which could achieve properties of mutual authentication, conditional anonymity, data confidentiality, unforgeability, undeniability, and data integrity. We utilize the digital signature algorithm CRYSTALS-Dilithium and the key-establishment algorithm CRYSTALS-KYBER, both of which have been selected for standardization by the National Institute of Standards and Technology, to realize secure access authentication for users of the quantum communication networks. Specifically, in the quantum secure direct communication network, key-establishment is replaced by the verification of signatures encoded in quantum states. Our results demonstrate the feasibility of establishing a quantum-secure communication network.

关键词： quantum communication quantum network access authentication post-quantum cryptography network control center

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