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arXiv 2019年

作者： Liu, Xiaoran Zhang, Xiaoying Zhang, Lei Xiao, Pei Wei, Jibo Zhang, Haijun Leung, Victor C.M. Department of Electronic Science National University of Defense Technology Changsha410073 China School of Engineering University of Glasgow GlasgowG12 8QQ United Kingdom 5G Innovation Centre Institute for Communication Systems University of Surrey GuildfordGU2 7XH United Kingdom Beijing Advanced Innovation Center for Materials Genome Engineering Beijing Engineering and Technology Research Center for Convergence Networks and Ubiquitous Services University of Science and Technology Beijing Beijing100083 China Department of Electrical and Computer Engineering University of British Columbia VancouverBCV6T 1Z4 Canada

Mixed-numerology transmission is proposed to support a variety of communication scenarios with diverse requirements. However, as the orthogonal frequency division multiplexing (OFDM) remains as the basic waveform, the peak-to average power ratio (PAPR) problem is still cumbersome. In this paper, based on the iterative clipping and filtering (ICF) and optimization methods, we investigate the PAPR reduction in the mixed-numerology systems. We first illustrate that the direct extension of classical ICF brings about the accumulation of inter-numerology interference (INI) due to the repeated execution. By exploiting the clipping noise rather than the clipped signal, the noise-shaped ICF (NS-ICF) method is then proposed without increasing the INI. Next, we address the in-band distortion minimization problem subject to the PAPR constraint. By reformulation, the resulting model is separable in both the objective function and the constraints, and well suited for the alternating direction method of multipliers (ADMM) approach. The ADMM-based algorithms are then developed to split the original problem into several subproblems which can be easily solved with closed-form solutions. Furthermore, the applications of the proposed PAPR reduction methods combined with filtering and windowing techniques are also shown to be effective. Copyright © 2019, The Authors. All rights reserved.

关键词： Orthogonal frequency division multiplexing

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Performance modeling of networked control systems

Performance modeling of networked control systems

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International Conference on Ultra Modern Telecommunications and Workshops (ICUMT)

作者： Paul J. Kuehn Sebastian Scholz Siyuan Cao Fei Li Institute of Communication Networks and Computer Engineering (IKR) University of Stuttgart Stuttgart Germany

Networked Control Systems (NCS) form a key element of Cyber-Physical Systems (CPS) where sensors, actuators (plants) and controller functions are spatially distributed and interconnected by communication networks. In this contribution models are developed where significant properties of communication networks such as stochastic delays, error control protocols and shared-network influences are embedded in a closed-loop control system. The resulting integrated systems are analyzed by methods of classical system-theoretic and discrete-time state analysis methods as well as by computer simulations. Fundamental insights in the properties of NCSs can already be gained through system-theoretic studies on basic architectures which provide closed-form expressions which are verified and extended by more detailed studies based on tool-supported discrete-time system state analysis and simulation-tool results. The approach allows for a more detailed detection of network protocol impacts on, e.g., the real-time behavior of NCSs when certain Service Level Agreements (SLA) have to be guaranteed as prescribed percentiles of control reaction times.

关键词： Delays Mathematical model Error correction Media Access Protocol Computational modeling Probability density function

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Single-drive high-speed lumped depletion-type modulators toward 10 fJ/bit energy consumption

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Photonics Research 2017年第2期5卷 134-142页

作者： XINBAI LI FENGHE YANG FANG ZHONG QINGZHONG DENG JURGEN MICHEL ZHIPING ZHOU State Key Laboratory of Advanced Optical Communication Systems and Networks School of Electronics Engineering and Computer SciencePeking University MIT Microphotonics Center Massachusetts Institute of Technology

Reduction of modulator energy consumption to 10 fJ∕bit is essential for the sustainable development of communication *** modulators might be a viable solution if instructed by a complete theory ***,we present a complete analytical electro-optic response theory,energy consumption analysis,and eye diagrams on absolute scales for lumped *** the speed limitation is understood and alleviated by single-drive configuration,and comprehensive knowledge into the energy dependence on structural parameters significantly reduces energy *** results show that silicon modulation energy as low as 80.8 and 21.5 fJ∕bit can be achieved at 28 Gbd under 50 and 10 Ω impedance drivers,respectively.A 50 Gbd modulation is also shown to be *** analytical models can be extended to lumped modulators on other material platforms and offer a promising solution to the current challenges of modulation energy reduction.

关键词： length type high

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IM-DD MDM-WDM transmission over 120-km weakly-conpled FMF enabled by wavelength interleaving

IM-DD MDM-WDM transmission over 120-km weakly-conpled FMF en...

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2017 Optical Fiber communications Conference and Exhibition, OFC 2017

作者： Tian, Yu Li, Juhao Wu, Zhongying Zhu, Paikun Chen, Yuanxiang Mo, Qi Ren, Fang Li, Zhengbin He, Yongqi Chen, Zhangyuan State Key Laboratory of Advanced Optical Communication Systems and Networks Peking University Beijing100871 China Wuhan Research Institute of Posts and Telecommunications Wuhan430074 China School of Computer and Communication Engineering Universitat of Science and Technology Beijing Beijing100083 China

Wavelength-interleaved (WI) scheme is proposed to mitigate modal crosstalk during weakly-coupled few-mode fiber (FMF) transmission based on which 2×3×10-Gb/s IM-DD MDM-WDM transmission over 120-km 2-mode FMF... 详细信息

ISBN: (纸本)9781943580231

关键词： Optical fibers

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Visible astro-comb filtered by a passively-stabilized Fabry-Perot cavity

arXiv

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arXiv 2018年

作者： Ma, Yuxuan Meng, Fei Liu, Yizhou Zhao, Fei Zhao, Gang Wang, Aimin Zhang, Zhigang State Key Laboratory of Advanced Optical Communication System and Networks School of Electronics Engineering and Computer Science Peking University Beijing100871 China National Astronomical Observatories of China Chinese Academy of Science Beijing100012 China National Institute of Metrology Beijing100029 China

We demonstrate a compact 29.3 GHz visible astro-comb covering the spectrum from 560nm to 700nm. A 837 MHz Yb:fiber laser frequency comb phase locked to a Rb clock served as the seed comb to ensure the frequency stability and high side mode suppression ratio. After the visible super-continuum generation, a cavity-length-fixed Fabry-Perot cavity made by ultra-low expansion glass was utilized to filter the comb teeth for eliminating the rapid active dithering. The mirrors were home-made complementary chirped mirrors pair with zero dispersion and high reflection to guarantee no mode skipping. These filtered comb teeth were clearly resolved in an astronomical spectrograph of 49,000 resolution, exhibiting sharp linetype, zero noise floor, and uniform exposure amplitude. Copyright © 2018, The Authors. All rights reserved.

关键词： Cavity resonators

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Towards SDN Based Queuing Delay Estimation

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China communications 2016年第3期13卷 27-36页

作者： MA Haiyan YAN Jinyao Panagiotis Georgopoulos Bernhard Plattner Faculty of Science and Technology Communication University of China Computer Engineering and Networks Laboratory Swiss Federal Institute of Technology Zurich (ETH Zurich)

As one of Qo S(Quality of Service) metrics, delay is critical important to delay sensitive applications, such as interactive video, network game and online surgery. In this paper, we exploit SDN(Software Defined Networking) advantages to solve delay Qo S problem. Our work mainly focuses on SDN based queuing delay estimation with real traffic and end-to-end delay control. First, we propose a queuing estimation model and extended it for end-to-end delay of the whole path. It is proved to be feasible and accurate with experimental results in SDN environment. Second, in order to demonstrate the use of our proposed model, we also implement an end-to-end delay control application in SDN. It fulfills specific delay Qo S requirements by dynamically switching flows to a suitable queue based on estimation results and delay requirements.

关键词： autonomic Qo S dynamic model delay performance SDN

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Towards adoption of an optical second: Verifying optical clocks at the SI limit

arXiv

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arXiv 2018年

作者： McGrew, W.F. Zhang, X. Leopardi, H. Fasano, R.J. Nicolodi, D. Beloy, K. Yao, J. Sherman, J.A. Schäffer, S.A. Savory, J. Brown, R.C. Römisch, S. Oates, C.W. Parker, T.E. Fortier, T.M. Ludlow, A.D. National Institute of Standards and Technology 325 Broadway BoulderCO80305 United States Department of Physics University of Colorado BoulderCO80309 United States State Key Laboratory of Advanced Optical Communication Systems and Networks Institute of Quantum Electronics School of Electronics Engineering and Computer Science Peking University Beijing100871 China Niels Bohr Institute University of Copenhagen Blegdamsvej 17 Copenhagen2100 Denmark

The pursuit of ever more precise measures of time and frequency is likely to lead to the eventual redefinition of the second in terms of an optical atomic transition. To ensure continuity with the current definition, based on a microwave transition between hyperfine levels in ground-state133Cs, it is necessary to measure the absolute frequency of candidate standards, which is done by comparing against a primary cesium reference. A key verification of this process can be achieved by performing a loop closure—comparing frequency ratios derived from absolute frequency measurements against ratios determined from direct optical comparisons. We measure the1S0 →3P0 transition of171Yb by comparing the clock frequency to an international frequency standard with the aid of a maser ensemble serving as a flywheel oscillator. Our measurements consist of 79 separate runs spanning eight months, and we determine the absolute frequency to be 518 295 836 590 863.71(11) Hz, the uncertainty of which is equivalent to a fractional frequency of 2.1 × 10−16. This absolute frequency measurement, the most accurate reported for any transition, allows us to close the Cs-Yb-Sr-Cs frequency measurement loop at an uncertainty of −16, limited by the current realization of the SI second. We use these measurements to tighten the constraints on variation of the electron-to-proton mass ratio, µ = me/mp. Incorporating our measurements with the entire record of Yb and Sr absolute frequency measurements, we infer a coupling coefficient to gravitational potential of kµ = (−1.9 ± 9.4) × 10−7 and a drift with respect to time ofµµ = (5.3 ± 6.5) × 10−17/yr. Copyright © 2018, The Authors. All rights reserved.

关键词： Frequency standards

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Preface

ICMLCA 2021 - 2nd International Conference on Machine Learni...

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ICMLCA 2021 - 2nd International Conference on Machine Learning and computer Application 2021年 iii页

作者： Ning, Xiansheng Feng, Yongxin Zhang, Wenbo Yue, Mingkai Du, Ke-Lin Huang, Shutao Zhou, Fang Ba, Shuhong Fu, Chong Shui, Penglang Xu, Shuwen Wu, Sheng Wang, Shushan Du, Zhonghua Gao, Zhijun Fan, Chunlong Li, Yufeng Wang, Yupeng Liu, Qingli Yu, Jingang Yin, Zhenyu Zhang, Deyu Gao, Hongwei Wen, Feng Guo, Cean Hao, Yongping Chan, Yung-Kuan Pavlovich, Vinogradov Gennady Kirpichnikova, Irina Qian, Zhihong Ivanov, Dmitriy V. Zhou, Xueguan Nezamabadi-Pour, Hossein Yang, Qing Zhang, Yongtang Liao, Haibin Huang, Ying Srinivasan, Kathiravan Xu, Zhenghua Pachori, Ram Bilas Zhang, Jialu AlShawabkeh, Mahmoud Guo, Chengjun Chaugule, Archana Ajit Lima, Alberto Sampaio Liu, Huayong Vidal, Jorge Maestre Alrshah, Mohamed A. Ghafoor, Kayhan Zrar Kubicek, Jan Chaugule, Archana Ajit Rodríguez-Pérez, Miguel Kumar, Gulshan Nasri, Mehdi Borrego, Carlos Persico, Valerio Wagh, Sanjeev Yan, Wenjun Yang, Li Yang, Dawei Xing, Yongkang Yang, Huadong Shang, Chengguo Chang, Xingong Shi, Hongbo Li, Aijun Feng, Liping Lv, Yali Liang, Minfu Wang, Kaixuan Bai, Zengliang Liang, Anhui Nan, Zhihong Ji, Suqin Chang, Liwei Zhou, Hongbin Yao, Chunli Cao, Guodong Zhang, Juling School of Information Science and Engineering Shenyang Ligong University China School of Equipment Engineering Shenyang Ligong University China Concordia University Canada School of Automotive and Transportation Shenyang Ligong University China School of Information Science and Engineering Shenyang Ligong University China School of Equipment Engineering Shenyang Ligong University China Northeastern University China Xidian University China Beijing University of Posts and Telecommunications China Beijing Institute of Technology China Nanjing University of Science & Technology China Shenyang Jianzhu University China Shenyang Aerospace University China Dalian University China Shenyang Institute of Computing Technology Chinese Academy of Sciences China Shenyang Ligong University China National Chun Hsing University Taiwan Department of Informatics and Applied Mathematics Russia South Ural State University Russia Jilin University China Samara State University of Transport Russia Naval Universit of Engineering China Shahid Bahonar University of Kermanto Iran Central China Normal University China Guangdong Neusoft Institute China Hubei University of Science and Technology China Liuzhou Railway Vocational Technical College China Vellore Institute of Technology India Hebei University of Technology China Indian Institute of Technology Indore India Xiangnan University China Guangxi Normal University for Nationalities China UESTC China Pimpri-Chinchwad College of Engineering & Research India Federal University of Ceará Brazil Complutense University of Madrid Spain Universiti Putra Malaysia Malaysia Shanghai Jiao Tong University China VŠB - Technical University of Ostrava Cuw Pimpri-Chinchwad College of Engineering & Research Ravet Pune India University of Vigo Spain Division of Research and Development India Islamic Azad University Iran Departament Enginyeria of Information Comunicacions Autonomous University of Barcelona Spain Opportunistic Networks United States Univers

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Interference modeling in clustered device-to-device networks with uniform transmitter selection

Interference modeling in clustered device-to-device networks...

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作者： Ding, Haiyang Wang, Xiaodong Da Costa, Daniel Benevides Ge, Jianhua State Key Laboratory of Integrated Service Networks Xidian University Xi'an710071 China Xi'an Communication Institute Xi'an710106 China Department of Electrical Engineering Columbia University New YorkNY10027 United States Department of Computer Engineering Federal University of Ceará Fortaleza62010-560 Brazil

This paper investigates the interference statistics in a clustered device-to-device network, where the cluster centers form a Poisson point process and each active receiver device selects the transmitter randomly following the uniform distribution. The statistics of the number of intra/inter-cluster interferers is first analyzed for both finite and infinite number of receivers per cluster. In addition, for the special cases where the numbers of transmitters and receivers differ significantly, simplified expressions are given. Then, using these derived probability distributions of the number of interferers, the Laplace transforms of intra/inter-cluster interference are established and simple approximations for the special cases are obtained as well. Our results show the following: 1) with the concurrent uniform transmitter selection, the distribution of the number of intra/inter-cluster interfering devices differs greatly from the truncated Poisson distribution assumed in the literature;2) the model assumed in the literature underestimates the coverage probability specially for a small number of transmitters/receivers;and 3) unlike the model assumed in the literature, the ASE of the proposed model increases with the number of transmitters/ receivers when the average number of active receivers is relatively small, while it does not monotonically vary with the number of transmitters/receivers when the average number of active receivers is large. © 2017 IEEE.

关键词： Transmitters

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PCL: Proposal cluster learning for weakly supervised object detection

arXiv

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arXiv 2018年

作者： Tang, Peng Wang, Xinggang Bai, Song Shen, Wei Bai, Xiang Liu, Wenyu Yuille, Alan School of Electronic Information and Communications Huazhong University of Science and Technology Wuhan430074 China Department of Engineering Science University of Oxford OxfordOX1 3PJ United Kingdom Key Laboratory of Specialty Fiber Optics and Optical Access Networks Shanghai Institute for Advanced Communication and Data Science School of Communication and Information Engineering Shanghai University Shanghai200444 China Departments of Cognitive Science and Computer Science Johns Hopkins University BaltimoreMD21218-2608 United States

Weakly Supervised Object Detection (WSOD), using only image-level annotations to train object detectors, is of growing importance in object recognition. In this paper, we propose a novel deep network for WSOD. Unlike previous networks that transfer the object detection problem to an image classification problem using Multiple Instance Learning (MIL), our strategy generates proposal clusters to learn refined instance classifiers by an iterative process. The proposals in the same cluster are spatially adjacent and associated with the same object. This prevents the network from concentrating too much on parts of objects instead of whole objects. We first show that instances can be assigned object or background labels directly based on proposal clusters for instance classifier refinement, and then show that treating each cluster as a small new bag yields fewer ambiguities than the directly assigning label method. The iterative instance classifier refinement is implemented online using multiple streams in convolutional neural networks, where the first is an MIL network and the others are for instance classifier refinement supervised by the preceding one. Experiments are conducted on the PASCAL VOC, ImageNet detection, and MS-COCO benchmarks for WSOD. Results show that our method outperforms the previous state of the art significantly. Copyright © 2018, The Authors. All rights reserved.

关键词： Object detection

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