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Lightwave Modulation Techniques for Advanced Modulation Formats

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China communications 2010年第3期7卷 35-42页

作者： Tetsuya Kawanishi National institute of Information and communications Technology (NICT)

Arbitrary waveform can be synthesized by two orthogonal components: in-phase and quadrature components. Thus, if we can manipulate the two components independently, various complicated modulation can be achieved. This technique is called vector modulation, which is commonly used in wireless radio communication systems where the carrier frequency is lower than 100GHz. On the other hand, in lightwave transmission systems, the carrier frequency is higher than 100THz, and the stability of the signal sources would be much poorer than in radio systems, so that the simplest modulation format (on-off-keying) was often used in commercial systems. However, recently, various modulation techniques such as quadrature amplitude modulation, etc., have been demonstrated by using precise and rapid lightwave control. In this report, we review recent progress in optical vector modulation technologies which can generate highspeed and complicated optical signals. Integrated optical modulators can synthesize multi-level signals in photonic circuits.

关键词： vector modulation integrated optical modulator photonic circuit

Investigation of Cross-Correlation Characteristics for Multi-Link Channels in High-Speed Railway Scenarios

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China communications 2018年第8期15卷 108-117页

作者： Tao Zhou Cheng Tao Liu Liu Kai Liu institute of Broadband Wireless Mobile communications Beijing Jiaotong University National Mobile communications Research Laboratory Southeast University

This paper investigates the cross-correlation characteristics of large-scale parameters(LSPs) and small-scale fading(SSF) for high-speed railway(HSR) multilink propagation scenarios, based on realistic measurements conducted on Beijing to Tianjin HSR line in China. A long-term evolution-based channel sounding system is utilized in the measurements to obtain the channel data. By applying a proposed time-delay based dynamic partition method, multi-link channel impulse responses are extracted from the raw channel data. Then, the statistical results of LSPs, including shadow fading, K-factor, and root-mean-square delay spread are derived and the cross-correlation coefficients of these LPSs are calculated. Moreover, the SSF spatial correlation and cross-correlation of SSF are analyzed. These results can be used to exploit multi-link channel model and to optimize the next-generation HSR communication system.

关键词： high-speed railway communications multi-link channel cross-correlation large-scale parameters small-scale fading.

Encoding syntactic representations with a neural network for sentiment collocation extraction

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Science China(Information Sciences) 2017年第11期60卷 7-18页

作者： Yanyan ZHAO Bing QIN Ting LIU Department of media Technology and Art Harbin Institute of Technology Department of Computer Science and Technology Harbin Institute of Technology

Sentiment collocation refers to the collocation of a target word and a polarity word. Sentiment collocation extraction aims to extract the targets and their modifying polarity words by analyzing the relationships between them. This can be regarded as a basic sentiment analysis task and is relevant in many practical applications. Previous studies relied mainly on the syntactic path, which is used to connect the target word and the polarity word. To deeply exploit the semantic information of the syntactic path, we propose two types of syntactic representation, namely, relation embedding and subtree embedding, to capture the latent semantic features. Relation embedding is used to represent the latent semantics between targets and their corresponding polarity words, and subtree embedding is used to explore the rich syntactic information for each word on the path. To combine the two types of syntactic representations, a neural network is constructed. We use a recursive neural network(RNN) to model the subtree embeddings, and then the subtree embedding and the word embedding are combined as the enhanced word representation for each word in the syntactic path. Finally,a convolutional neural network(CNN) is adopted to integrate the two types of syntactic representations to extract the sentiment collocations from reviews. Our experiments were conducted on six types of reviews, which included product domains(such as cameras and phones) and service domains(such as hotels and restaurants).The experimental results show that our proposed method can accurately capture the latent semantic features hidden behind the syntactic paths that neither the common feature-based methods nor the syntactic-path-based method can handle, and, further, that it significantly outperforms numerous baselines and previous methods.

关键词： sentiment collocation extraction sentiment analysis syntactic representation neural network re cursive neural network(RNN) convolutional neural network(CNN)

A nut-type ultrasonic motor and its application in the focus system

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Chinese Science Bulletin 2009年第20期54卷 3778-3783页

作者： ZHOU TieYing ZHANG Yun CHEN Yu LU CunYue FU DeYong LI Yi HU XiaoPing Department of Physics Tsinghua University Beijing 100084 China Boly media communications LTD (Shenzhen) Shenzhen 518031 China

This article reports a screw-driven polyhedron linear ultrasonic motor(USM) of *** is comprised of a stator,which is a threaded metal nut bonded with piezoelectric plates on its external surface,and a rotor with external threads,which engage with the internal threads of the stator.A traveling wave in the plane is stimulated on the stator when harmonic electric signals are applied to the piezoelectric *** traveling wave drives the rotor to rotate,and the threads transform the rotation into a linear *** lens can be fixed in the rotor and realize the integrated design of the auto focus *** structure can omit retarder and directly drive to obtain a high accuracy of positioning,and it is shockproof.A mini AF cellular phone module(8.5 mm×8.5 mm×5.9 mm) driven by this motor was made and an image resolution of 3-5 MP was obtained in the module prototypes of the cellular phone.

关键词：自动对焦系统超声波电机螺母应用直线运动直接驱动迷你手机超声波马达

Label swapping and packet transmission of DPSK-labeled PPM signal in optical label switching

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Chinese Optics Letters 2011年第8期9卷 11-15页

作者：师严张琦余重秀忻向军金沧周锐 institute of Information Photonics and Optical communications Beijing University of Posts and Telecommunications

A label swapping scheme of an optical labeled signal with differential phase shift keying （DPSK） for label at 2.5 Gb/s and pulse position modulation （PPM） for payload at 40 Gb/s is demonstrated by simulation. Power penalties of -1.8 and -0.8 dB are achieved for both the payload and label over 80-kin single mode fiber （SMF） transmission. This labeling scheme allows the use of four-wave mixing （FWM） in semiconductor optical amplifier （SOA） to perform label erasure, with advantages of transparence for bit rate, high processing rate, simple architecture, and low cost. Label swapping is demonstrated with appropriate penalties of -3.5 and 0.8 dB for PPM payload and new DPSK label, respectively. To further prove the effectiveness of the proposed scheme, label swapping in the case of using 10-Gb/s DPSK label is also investigated with the nnwer penaltios af tq *** P dR fnr PPM paylnnrl and new dPRIC lnhol

关键词： Four wave mixing Light amplifiers Pulse position modulation Single mode fibers

An Intermediate Frequency Acquisition Scheme for S-band Single Access Link of the Tracking and Data Relay Satellite System

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High Technology Letters 2001年第1期7卷 31-36页

作者：马雨出 Gu Xuemai Zhang Naitong communications Research Center Harbin Institute of Technology

A nonzero intermediate frequency (IF) likelihood acquisition scheme designed for S-band Single Access (SSA) link of China’s Tracking and Data Relay Satellite System (CTDRSS) is introduced. The received signal is downconverted to IF, and then direct sampled in IF using a 1-bit A/D. After the digitalization, the sampled data is detected using a hybrid likelihood acquisition scheme. Using this structure, large noise figure of the analog mixer or active filters, amplitude and phase imbalance between low-frequency in-phase and quandrature-phase channel can be avoided. An easy designing algorithm of the acquisition scheme is also derived. The performance and algorithm are verified by computer simulation.

关键词： Digital receiver Likelihood detector PN code acquisition Satellite communications

Huge capacity spacial division multiplexing transmission and integrated optical switching technologies(Invited Paper)

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Chinese Optics Letters 2016年第12期14卷 12-16页

作者： Naoya Wada Ben J.Puttnam Ruben S.Luis Werner Klaus Jun Sakaguchi Jose M.D.Mendinueta Yoshinari Awaji Satoshi Shinada Hideaki Furukawa National institute of Information and communications Technology Tokyo 184-8795 Japan

We review the research and development of beyond Pb/s capacity space-division-multiplexed transmission technology using multi-core optical fibers for satisfying the ever-increasing traffic demand. Moreover, we present an optical packet and circuit integrated network technology to improve switching capacity and flexibility in network nodes for the rapid traffic fluctuation and the data service diversification.

关键词： switching multiplexing satisfying fluctuation traffic packet frames transmit throughput overhead

Torsionally coupled dynamic performance analysis of asymmetric offshore platforms subjected to wave and earthquake loadings

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Earthquake Engineering and Engineering Vibration 2010年第2期9卷 247-258页

作者： He Xiaoyu and Li Hongnan 1.Zhejiang Provincial Planning,Design & Research institute of communications,Hangzhou 310006,China 2.State Key Laboratory of Coastal and Offshore Engineering,Dalian University of Technology,Dalian 116024,China Zhejiang Provincial Planning Design & Research Institute of Communications Hangzhou 310006 China

The dynamic equations of motion of asymmetric offshore platforms under three different environmental conditions:seismic action,wave action and their combination are established in this paper. In establishing these motion equations,three typical eccentricity types including mass eccentricity,rigidity eccentricity and their combination were considered,as are eccentricities that occur un-idirectionally and bi-directionally. The effects of the eccentricity type,the dynamic characteristics and the environmental conditions on the torsional coupling response of platforms are investigated and compared. An effort has also been made to analyze the inffluence of accidental eccentricity on asymmetric platforms with different eccentricity in two horizontally orthogonal directions. The results are given in terms of non-dimensional parameters,accounting for the uncoupled torsional to lateral frequency ratio. Numerical results reveal that the eccentricity type has a great inffluence on the torsionally coupled response under different environmental conditions. Therefore,it is necessary to consider the combination of earthquake and wave action in the seismic response analysis of some offshore platforms.

关键词： offshore platform asymmetric structure accidental eccentricity torsion coupling earthquake load wave load

Study of FSK/IM orthogonal modulation system with optical Manchester-coded payload

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Chinese Optics Letters 2010年第5期8卷 464-467页

作者：周锐忻向军张琦赵堃赵同刚余重秀 institute of Information Photonics and Optical communications Beijing University of Posts and Telecommunications

We study the performance of an orthogonal modulation system with frequency-shift keying（FSK） label and optical Manchester-coded（MC） *** result shows that by introducing an optical MC payload,the available extinction ratio（ER） value of a FSK and intensity modulation（IM） orthogonal modulation system can be improved from 5 to 9 dB for system optimization,exhibiting great advantages over the traditional non-return-to-zero（NRZ） ***,the bit error rate（BER） characteristics of both label and payload show a more remarkable advantage than that of NRZ coding,verifying itself as a perfect candidate for the payload coding method in orthogonal modulation systems.

关键词： Bit error rate Labels Optical communication