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Efficient separating orbital angular momentum mode with radial varying phase

Photonics Research 2017年第4期5卷 267-270页

作者： CHENG LI SHENGMEI ZHAO Institute of Signal Processing and Transmission Nanjing University of Posts and Telecommunications Key Lab of Broadband Wireless Communication and Sensor Network Technology Ministry of Education

It is shown that orbital angular momentum(OAM) is a promising new resource in future classical and quantum communications. However, the separation of OAM modes is still a big challenge. In this paper, we propose a simple and efficient separation method with a radial varying phase. In the method, specific radial varying phases are designed and modulated for different OAM modes. The resultant beam is focused to the spots with different horizontal and vertical positions after a convex lens, when the coordinate transformation, including two optical elements with coordinate transformation phase and correct phase, operates on the received *** horizontal position of the spot is determined by the vortex phases, and the vertical position of the spot is dependent on the radial varying phases. The simulation and experimental results show that the proposed method is feasible both for separation of two OAM modes and separation of three OAM modes. The proposed separation method is availab.e in principle for any neighboring OAM modes because the radial varying phase is controlled. Additionally, no extra instruments are introduced, and there is no diffraction and narrowing process limitation for the separation.

关键词： OAM Efficient separating orbital angular momentum mode with radial varying phase mode

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A Simple Method on Generating any Bi-Photon Superposition State with Linear Optics

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communications in Theoretical Physics 2017年第4期67卷 391-395页

作者：张婷婷魏杰王琴 Institute of Signal Processing and Transmission Nanjing University of Posts and TelecommunicationsNanjing 210003China Key Laboratory of Broadband Wireless Communication and Sensor Network Technology Nanjing University of Posts and TelecommunicationsMinistry of EducationNanjing 210003China Key Laboratory of Quantum Information CASUniversity Science and Technology of ChinaHefei 230026China

We present a simple method on the generation of any bi-photon superposition state using only linear *** this scheme, the input states, a two-mode squeezed state and a bi-photon state, meet on a beam-splitter and the output states are post-selected with two threshold single-photon detectors. We carry out corresponding numerical simulations by accounting for practical experimental conditions, calculating both the Wigner function and the state fidelity of those generated bi-photon superposition states. Our simulation results demonstrate that not only distinct nonclassical characteristics but also very high state fidelities can be achieved even under imperfect experimental conditions.

关键词： bi-photon superposition state Wigner function state fidelity

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A Toeplitz Covariance Matrix Reconstruction Approach for Direction-of-Arrival Estimation

A Toeplitz Covariance Matrix Reconstruction Approach for Dir...

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作者： Wu, Xiaohuan Zhu, Wei-Ping Yan, Jun Key Lab of Broadband Wireless Communication and Sensor Network Technology Nanjing University of Posts and Telecommunications Nanjing210003 China Department of Electrical and Computer Engineering Concordia University Montreal QC210003 Canada

It is known that there exist two kinds of methods for direction-of-arrival (DOA) estimation in the literature: the subspace-based method and the sparsity-based method. However, pervious works reveal that the former method cannot address the case in which the number of signals is larger than that of sensors, whereas the latter one always suffers from the influence of basis mismatch. In this paper, to overcome these two shortcomings, we propose a new method called covariance matrix reconstruction approach (CMRA) for both uniform linear array and sparse linear array. In particular, by exploiting the Toeplitz structure of the covariance matrix of the array output, we formulate a low-rank matrix reconstruction (LRMR) problem for covariance matrix recovery. The nonconvex LRMR problem is then relaxed by replacing the rank norm with the nuclear norm and solved using the optimization toolbox. Next, we retrieve the DOAs from the recovered covariance matrix by using the subspace-based methods and obtain an estimated number of signals as a byproduct. We also provide two algorithm implementations for the LRMR problem based on duality and alternating direction method of multipliers, respectively. It is shown that CMRA can be regarded as an atomic norm minimization model or a gridless version of the sparsity-based methods and can recover more signals than sensors with a well-designed array. Numerical experiments are provided to validate the effectiveness of the proposed method, in comparison with some of the existing methods. © 1967-2012 IEEE.

关键词： Covariance matrix

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Dynamic priority algorithm for modern tram based on MADM 2

Dynamic priority algorithm for modern tram based on MADM

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2nd IEEE International Conference on Intelligent Transportation Engineering, ICITE 2017

作者： Wu, Jiaqi Yu, Yang Lin, Xiaoyong College of Transportation Science and Technology Nanjing Tech University Nanjing210009 China Key Lab of Broadband Wireless Communication and Sensor Network Technology Nanjing University of Posts and Telecommunications Ministry of Education Nanjing210003 China

ISBN: (纸本)9781509062720

Analyzing the influence on traffic flow at intersection according to the driving characteristics of modern tram with different lane layout types. Proposing a method of dynamic priority algorithm (DPA) based on the idea of multiple attribute decision making (MADM) to analyze intersection delay. The VAP module based on MATlab.in Vissim is used to simulate the induction control of the modern tram through the concrete intersection, mainly analyzing delay of the intersection with different lane layout types of modern trams. Taking the intersection of Middle Jiangdong Road and Hexi Avenue in Nanjing as an example, the traffic delay caused by different lane layout of modern tram is analyzed by using absolute priority and dynamic priority algorithm (DPA) respectively. © 2017 IEEE.

关键词： MATlab

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Adaptive spatial modulation for visible light communications with an arbitrary number of transmitters

arXiv

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arXiv 2018年

作者： Wang, Jin-Yuan Ge, Hong Zhu, Jian-Xia Wang, Jun-Bo Dai, Jianxin Lin, Min Key Lab of Broadband Wireless Communication and Sensor Network Technology Nanjing University of Posts and Telecommunications Nanjing210003 China National Mobile Communications Research Laboratory Southeast University Nanjing210096 China School of Science Nanjing University of Posts and Telecommunications Nanjing210003 China

As a power and bandwidth efficient modulation scheme, the optical spatial modulation (SM) technique has recently drawn increased attention in the field of visible light communications (VLC). To guarantee the number of bits mapped by the transmitter's index at each timeslot is an integer, the number of transmitters (i.e., light-emitting diodes) in the SM based VLC system is often set be a power of two. To break the limitation on the required number of transmitters and provide more design flexibility, this paper investigates the SM based VLC with an arbitrary number of transmitters. Initially, a channel adaptive bit mapping (CABM) scheme is proposed, which includes three steps: Bit mapping in space domain, bit mapping in signal domain, and the channel adaptive mapping. The proposed CABM scheme allows operation with an arbitrary number of transmitters, and is verified to be an efficient scheme through numerical results. Based on the CABM scheme, the information-theoretical aspects of the SM based VLC are analyzed. The theoretical expression of the mutual information is first analyzed. However, it is very hard to evaluate system performance. To obtain more insights, a lower bound of the mutual information is derived, which is in closedform. Both theoretical analysis and numerical results show that the gap between the mutual information and its lower bound is small. Finally, to further improve the system performance, the precoding scheme is proposed for the SM based VLC. Numerical results show that the system performance improves dramatically when using the proposed precoding scheme. Copyright © 2018, The Authors. All rights reserved.

关键词： Visible light communication

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Towards secure data sharing in cloud computing using attribute based proxy re-encryption with keyword search

Towards secure data sharing in cloud computing using attribu...

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IEEE International Conference on Cloud Computing and Big Data Analysis (ICCCBDA)

作者： Hanshu Hong Zhixin Sun Network Technology Lab of Broadband Wireless Communication and Sensor Nanjing China

ISBN: (纸本)9781509045006

Cloud computing plays a significant role in big data era since it can provide dynamic, scalab.e virtual resource services via the Internet. However, how to enhance the security level of cloud computing is a challenging issue which is urgently to be tackled. In this paper, we center on the data security in cloud computing and present an attribute based proxy re-encryption scheme with keyword search (ABPRE-KS) to provide flexible and secure data sharing among users in the cloud. In our scheme, a user's access privileges are described by an access structure consisting of several attributes while ciphertexts are lab.led by several target attributes. A delegator can transform the original ciphertexts into proxy ciphertexts encrypted by the delegatee's attributes without leaking any sensitive information to the cloud server. Besides, a search request on the ciphertexts is allowed by a delegatee if his credentials satisfy the delegatee's access policy. By security analysis, our ABPRE-KS is confidential and keyword semantic secure under BDBH assumption.

关键词： Ciphers Indexes

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High-dimensional measurement-device-independent quantum key distribution based on spatial basis

arXiv

引用

arXiv 2018年

作者： Li, Wei Zhao, Shengmei Nanjing University of Posts and Telecommunications Institute of Signal Processing and Transmission Nanjing210003 China Nanjing University of Posts and Telecommunications Key Lab Broadband Wireless Communication and Sensor Network Ministy of Education Nanjing210003 China Sunwave Communications Hangzhou310053

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An Integrated Optimization Model for Urban Agglomeration Traffic and Land Use Based on Multi-objective Particle Swarm Optimization Algorithm

An Integrated Optimization Model for Urban Agglomeration Tra...

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IEEE International Conference on Intelligent Transportation Engineering (ICITE)

作者： Jiaqi Wu Yang Yu Wenqiang Xue Qinyuan Zhang College of Transportation science & Technology Nanjing Tech University Nanjing Key Lab of Broadband Wireless Communication and Sensor Network Technology of Ministry of Education Nanjing University of Posts and Telecommunications Nanjing YangZhou Urban Planning and Research Geography Information Information Center Hexi Campus International Department Jinling High School

Based on the mutual relationship between traffic and land use, the Integrated Transportation and Land Use Model (ITLM) is established from the perspective of urban agglomeration development. The model parameters are calibrated by using MATlab.and ArcGIS in combination with information entropy model and Multi-objective Particle Swarm Optimization. From the macro and meso perspectives, the space syntax is used to quantify the transport links of cities in urban agglomerations. Taking the Yangtze River City Group as an example, combined with big data analysis by POI, after optimization of the land use area, population size, and traffic structure of various types of nature through the ITLM model, traffic occurrence and attraction of cities in urban agglomerations tend to be more balanced than the current situation. It plays a vital role in analyzing the current status of cities in urban agglomerations and promoting the further development of urban agglomerations.

关键词： Urban areas Transportation Sociology Statistics Mathematical model Optimization Particle swarm optimization

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Voiceprint recognition based on BP Neural network and CNN

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Journal of Physics: Conference Series 2019年第3期1237卷

作者： Dong Zhipeng Wei Jingcheng Xu Yumin Meng Qingmin Wang Xiaoming Key Laboratory of Broadband Wireless Communication and Sensor Network Technology (Nanjing University of Posts and Telecommunications) Ministry of Education College of Telecommunications & Information Engineering Nanjing 210003 China National Mobile Communications Research Lab Southeast University Nanjing 210096 China

At present, speech recognition has become a key technology of human-computer interaction, which can be used in semantic recognition and speaker identification and other related applications. This paper focuses on a speaker identification scene and the technical design. Because artificial neural network has the ability to distinguish complex classification boundaries, plenty of work on speech recognition had studied multi-layer perceptual networks to improve the accuracy of classification where back propagation method (BP algorithm) has been used. In the studied scheme, when the test objects (speakers) speak the same isolated word, the identification system can judge who the speaker is by identifying the voice voiceprint of different people. Our design not only considers the recognition based on BP as well as its variant, but also explores the voiceprint recognition based on convolution neural network (CNN). Secondly, the network structure and performance are also compared in detail.

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Reconfigurable vortex beam generator based on the Fourier transformation principle

arXiv

引用

arXiv 2018年

作者： Liu, Aiping Zou, Chang-Lin Ren, Xifeng He, Wen Wu, Mengze Guo, Guangcan Wang, Qin Affiliation: Institute of Quantum Information and Technology Nanjing University of Posts and Telecommunications Nanjing210003 Key Lab of Broadband Wireless Communication and Sensor Network Technology Nanjing University of Posts and Telecommunications Ministry of Education Nanjing210003 Synergetic Innovation Center of Quantum Information and Quantum Physics University of Science and Technology of China Hefei230026 China

A method to generate the optical vortex beam with arbitrary superposition of different orders of orbital angular momentum (OAM) on a photonic chip is proposed. The distributed Fourier holographic gratings are proposed to convert the propagating wave in waveguides to a vortex beam in the free space, and the components of different OAMs can be controlled by the amplitude and phases of on-chip incident light based on the principle of Fourier transformation. As an example, we studied a typical device composed of nine Fourier holographic gratings on fan-shaped waveguides. By scalar diffraction calculation, the OAM of the optical beam from the reconfigurable vortex beam generator can be controlled on-demand from ?2nd to 2nd by adjusting the phase of input light fields, which is demonstrated numerically with the fidelity of generated optical vortex beam above 0.69. The working bandwidth of the Fourier holographic grating is about 80 nm with a fidelity above 0.6. Our work provides an feasible method to manipulate the vortex beam or detect arbitrary superposition of OAMs, which can be used in integrated photonics structures for optical trapping, signal processing, and imaging. Copyright © 2018, The Authors. All rights reserved.

关键词： Incident light

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